United States National Library of Medicine National Institutes of Health

MEDLINE®/PubMed® Data Element (Field) Descriptions

This document describes the major elements (or fields) found on the MEDLINE display format for PubMed MEDLINE records. Some elements (e.g., Comment In) are not mandatory and will not appear in every record. Other elements (e.g., Author, MeSH term, Registry Number) may appear multiple times in one record. Some of the elements on this list are searchable fields in PubMed. For searching instructions, see the Search Field Tags section of PubMed Help. This document is supplementary information, to be used in conjuction with PubMed Help. MEDLINE/PubMed XML data element descriptions are also available.

PubMed MEDLINE display elements are presented in this section in alphabetical order, except in the case of certain elements that are closely related to one another.

Abstract (AB)
Copyright Information
Investigator Affiliation
Article Identifier
Full Author
Corporate Author
Date Completed
Date Created
Date Last Revised
Date of Electronic Publication
Date of Publication
Entrez Date
Gene Symbol
General Note
Grant Number (GR)
Investigator Name and Full Investigator Name
Journal Title Abbreviation (TA)
Journal Title (JT)
Location Identifier (LID)
Manuscript Identifier (MID)
MeSH Date
MeSH Terms
NLM Unique ID
Number of References
Other Abstract
Other Copyright Information
Other ID
Other Term
Other Term Owner
Personal Name as Subject
Full Personal Name as Subject (FPS)
Place of Publication (PL)
Publication History Status
Publication Status
Publication Type
Publishing Model
PubMed Central Identifier (PMC)
PubMed Unique Identifier
Registry Number/EC Number
Substance Name
Secondary Source ID
Space Flight Mission
Transliterated Title

Abstract (AB)

English-language abstracts are taken directly from the published article. If the article does not have a published abstract, the National Library of Medicine does not create one, thus the record lacks the Abstract element. If a collaborating data producer has created an abstract, it will appear in the Other Abstract (OAB) field. This field may be used in addition to or instead of Abstract.

Publishers have given the National Library of Medicine permission to use abstracts for which they claim copyright. NLM does not hold copyright on the abstracts in MEDLINE. Users should obtain an opinion from their legal counsel for any use they plan for the abstracts in the database.

Generally, there are no abstracts for records created before 1975. However, starting in April 2007 NLM began to add abstracts from articles in PubMed Central (PMC) to the equivalent MEDLINE/PubMed citation record if that record does not already contain an abstract. The abstracts are derived from the PMC scanning project which is digitizing the back issues of participating PMC journals. As a result, additional records published prior to 1975 will contain abstracts.

All abstracts are in English. Because data entry policies at NLM have changed over the years, abstracts in some records may be truncated, in which case one of the following phrases may appear at the end of the text enclosed in parentheses:

ABSTRACT TRUNCATED (This message occurred infrequently once the maximum length was raised to 4,096 characters in 1996.)


AB - Many disorders may result in delay of language. . . . . The reason for suggesting this diagnostic category is to stress that these children do initially behave in a similar way to those who are peripherally deaf. (ABSTRACT TRUNCATED AT 250 WORDS)

The maximum length of abstracts for records created after 2000 is 10,000 characters. Original policy on inclusion of abstracts set a limit of 250 words for acceptance. Effective with the January 1984 data (i.e., NLM's ELHILL legacy system 8401 Entry Month) two changes were made in this policy: 1) the word limit was expanded to 400 words for abstracts from articles ten pages or more in length or from articles in the core journals identified by the National Cancer Institute and 2) abstracts exceeding the 250- or 400-word limit are to be included in truncated form at the end of the sentence closest to the word limit. The percentage of records with abstracts has increased over the years as more publishers gave permission for NLM to include these data. A chart showing the number of MEDLINE records containing abstracts in various segments of MEDLINE is available at: http://www.nlm.nih.gov/bsd/medline_lang_distr.html.

Structured abstracts, describing key aspects of the purposes, methods, and results in a consistent way, are published in some journals. The key aspects of structured abstracts are capitalized to stand out, e.g., BACKGROUND, OBJECTIVES, METHOD, etc. The text is not broken into paragraphs. Structured abstracts were not truncated in the past, even if they surpassed the previous 250 or 400 word limit.


AB - BACKGROUND: Superantigens produced by Staphylococcus aureus and Streptococcus pyogenes are among the most lethal of toxins. Toxins in this family trigger an excessive cellular immune response leading to toxic shock. OBJECTIVES: To design an antagonist that is effective in vivo against a broad spectrum of superantigen toxins. METHODS: Short peptide antagonists were selected for their ability to inhibit superantigen-induced expression of human genes for cytokines that mediate shock. The ability of these peptides to protect mice against lethal toxin challenge was examined. RESULTS: Antagonist peptide protected mice against lethal challenge with staphylococcal enterotoxin B and toxic shock syndrome toxin-1, superantigens that share only 6% overall amino acid homology. Moreover, . . .

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Copyright Information (CI)

Copyright Information (CI) associated with Abstract was introduced in 1999, and appears on a limited but increasing number of records. This singly-occurring element contains a copyright statement provided by the publisher of the journal and appears only on records supplied electronically to NLM by the publisher. This information is displayed at the end of the abstract.


AB - ... Copyright 1999 Academic Press.

See also the related Other Copyright Information (OCI) field.

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Affiliation (AD)

The affiliation of the first author resides in this field. Starting in 1988, NLM began to include the address of the first author's affiliation on the record. Originally, the address was intended to help differentiate between two authors of the same name, not to provide detailed mailing information. It evolved that the institution, city, and state including zip code for U.S. addresses, and country for countries outside of the United States, were included if provided in the journal; sometimes the street address was also included if provided in the journal. In 1995, NLM began to add the designation USA at the end of this information where the first author's affiliation is in the fifty United States or the District of Columbia. Effective January 1, 1996, NLM includes the primary author's electronic mail (e-mail) address at the end of the Affiliation field, if present in the journal. Starting in 2003 the complete first author address is entered as it appears in the article with no words omitted.


AD - Department of Anesthesiology, University of Virginia Health Sciences Center Charlottesville 22908, USA. med2p@virginia.edu

AD - Departamento de Farmacologia, Facultad de Medicina, Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain.

AD - Center for Children With Special Needs, Children's Hospital, and the Department of Pediatrics, University of Washington School of Medicine, 4800 Sand Point Way NE, CM:09, Seattle, WA 98105-0371, USA. jneff@chmc.org

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Investigator Affiliation (IRAD)

The Investigator Affiliation (IRAD) occurs only for data created by one of our former collaborating data producers, the National Aeronautics and Space Administration (NASA). It identifies the organization that the researcher was affiliated with at the time the article was written and as published in the journal. Unlike the Affiliation field associated with the Author field, this affiliation generally does not include detailed address information. This field is associated with the Investigator Name (IR) field, also created by NASA.


IRAD - Marquette U, Milwaukee, WI
IRAD - VA Med Ctr, Richmond, VA

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Article Identifier (AID)

This field is populated by the publisher. It may contain an identifier that links with records in the publisher's system. The article identifier values may include the controlled publisher identifier (PII) or the digital object identifier (DOI). It is most often used for LinkOut, and is not considered part of the citation source information.


AID - S0272-7358(05)00023-1 [pii]
AID - 10.1016/j.cpr.2005.02.002 [doi]

Beginning in April 2008, DOI and PII data is included in the Location Identifier (LID) field. The information in the LID field is considered part of the citation source.

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Author (AU)

NLM's author indexing policy is explained in the Fact Sheet: Authorship in MEDLINE.

Limitations to the number of author names included in MEDLINE are as follows:

1966 - 1983: For records created during this time period, MEDLINE did not limit the number of authors.
1984 - 1995: For records created during this time period, NLM limited the number of authors to 10, with "et al." to indicate the existence of additional authors. This practice began with citations created on October 29, 1983.
1996 - 1999: For journal issues published during this time period, NLM increased the number of authors from 10 to 25. If there were more than 25 authors, the first 24 were listed, the last author was used as the 25th, and the 26th and beyond became "et al."
2000 - Present: Beginning with journal issues published in 2000, MEDLINE does not limit the number of listed authors.

Beginning in mid-2005, the various policy restrictions on number of author names entered in past years were lifted so that on an individual basis, a record may be edited to include all author names present in the published article, regardless of the limitation in effect at the time the record was first created.

Effective with 1992 date of publication, letters are indexed individually with authors rather than as an anonymous group.

Note: Until 1990, NLM transliterated up to five authors' Cyrillic or Japanese names to the Roman alphabet. Since 1990, the first ten Cyrillic or Japanese names are transliterated. Chinese ideograms are not transliterated by NLM, but if transliterations of the authors names are available in the journal article or table of contents, they are included in the citation, even if that includes only one author in a multi-author article.

Format: last name followed by a space and up to the first two initials followed by a space and a suffix abbreviation, if applicable, all without periods or a comma after the last name.


McCrary SV
Smith AB 3rd

See Full Author (FAU) for more information on initials.

See also Corporate Author (CN).

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Full Author (FAU)

Beginning with articles with a publication year of 2002, PubMed records may include full names. BIOETHICSLINE citations converted to MEDLINE citations in late 2001 have full names on citations prior to publication year 2002; those data are found in the General Note (GN) field. Citations from the Kennedy Institute of Ethics (KIE) may have full names in the Full Author field for publication dates of prior to 2002.

Full author names are entered when they appear in the author position of an article, usually on the title page of an article. If only the last name and initials appear in the author position, then only the last name and initials will be entered, even if a form of the fuller name appears elsewhere in the article or in the Table of Contents for the journal.

Author Initials:
Initials data are generated from the Data Creation and Maintenance System (DCMS) ForeName data element using an algorithm. Here are the highlights of that algorithm:


Last Name Fore Name Suffix Initials
Melosh H J 3rd HJ
Abrams Judith J
Buncke Gregory M GM
Gonzales-loza Maria del R Mdel R
Dubuisson Jean-Bernard JB
Amara Mohamed el-Walid Mel-W
Shan Yu-fei YF
Krylov Ia K IaK
De Avila Luiz Francisco Rodriguez LF

Note that the end result of generating the Initials data is that the two initials are closed up with no space between, even though there may be spaces elsewhere in the Initials string if one or both of the initials has embedded spaces.

There are some author names that have no initials. These are mostly Malaysian names, for which the entire name is entered in the LastName DCMS data element.

The full name will display on the PubMed MEDLINE display format above the respective name field as in the following example:


FAU - Foa, Edna B
AU - Foa EB

Note: When an author's name has been corrected from a published erratum, the corrected name is placed in the Author field and the incorrect name that was originally published is retained in the last occurrence of the Author field. In this case, there will be an associated commentary linkage.

NLM expended much effort to parse the data converted from the legacy ELHILL format at the end of the 2000 production year accurately. Many citations from the 1966-1974 timeframe were changed to follow data entry conventions established later. For example, particles such as "van der" were moved from the suffix position to the beginning of the last name, and the abbreviations "2d" and "3d" were changed to "2nd" and "3rd". It is possible to have particles associated with initials, such as "Mdel R" for "María del R". It is also possible to have only a last name. Some occurrences of author data in this category are in error and will be corrected manually as time permits.

For OLDMEDLINE records, every published author name is included in the list of authors for citations from the 1951 - 1959 Current List of Medical Literature (CLML) and for citations from the 1960 - 1965 Cumulated Index Medicus (CIM). For citations from the 1950 CLML, a maximum of three author names were entered. OLDMEDLINE first and last name author elements are in all upper case letters, except in some cases the particle is in lower case letters. A suffix is in upper and lower case letters. OLDMEDLINE records do not contain collective or corporate names. A small percentage of OLDMEDLINE records contain the last name only, because that is the only Author data present in the abstracting and indexing tool used to create the record.

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Corporate Author (CN)

This field identifies the corporate authorship of an article. Corporate Author (CN) was introduced in 2001. NLM's author indexing policy is explained in the Fact Sheet: Authorship in MEDLINE.

These names enter MEDLINE exactly as they appear in the journal (except to delete initial articles such as The, A or An). NLM will not edit the names to standardize them or translate them into English. NLM enters the Roman alphabet words (e.g., German, French) into the Corporate Author field. Transliterated Russian or other cyrillic names are also entered into the Corporate Author field, but for Japanese, Chinese, Hebrew, and Arabic, NLM puts the English translation of the name into this field.


CN - Centers for Disease Control and Prevention

From 2001 to April 2006, the corporate author name displayed in PubMed citations as the last occurrence in the author field, as a separate data element after any personal names. Effective May 2006, the collective author is retained in the order of all authors found in the byline of the published article. See the May-June 2006 Technical Bulletin article for details.

Citations prior to 1966, in general, have no indication of collective author unless they were created by NLM's data creation partners. Citations from 1966 to 2000 with collective author field data contain that data in the Title field. These records are generally those created by NLM's data creation partners, and are very few in number and typically in the population or ethics subject areas. As they are encountered, these retrospective records may be individually maintained to move the Corporate Author information from the Title field to the Corporate Author field.

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Comments/Corrections (See fields and field tags listed below.)

The data in these fields, listed below, are citations to associated journal publications, e.g., comments, errata, or retractions. These data enable links between the record at hand and its associated citations.

MEDLINE records may contain one or more of the following. See more detailed information about the policy for each type of comment or correction. To search PubMed for records with comments or corrections, see PubMed Help.

Comment or Correction Type MEDLINE Display Field Tag Description
Comment on (CON) cites the reference upon which the article comments; began use with journal issues published in 1989.
Comment in (CIN) cites the reference containing a commentary about the article (appears on citation for original article); began use with journal issues published in 1989.
Erratum in (EIN) cites a published erratum to the article (appears on citation for original article); began use in 1987.
Erratum for (EFR) cites the original article for which there is a published erratum.
Corrected and Republished in (CRI) cites the final, correct version of a corrected and republished article (appears on citation for original article). Began use in 1987 as Republished in (RPI); renamed in 2006.
Corrected and Republished from (CRF) cites the original article subsequently corrected and republished. Began use in 1987 as Republished from (RPF); renamed in 2006.
Partial retraction in (PRIN) cites the reference containing a partial retraction of the article (appears on citation for original article); began use in 2007.
Partial retraction of (PROF) cites the article being partially retracted; began use in 2007.
Republished in (RPI) cites the subsequent (and possibly abridged) version of a republished article (appears on citation for original article); began use in 2006.
Republished from (RPF) cites the first, originally published article; began use in 2006.
Retraction in (RIN) cites the retraction of the article (appears on citation for original article); began use in August 1984.
Retraction of (ROF) cites the article(s) being retracted; began use in August 1984.
Update in (UIN) cites an updated version of the article (appears on citation for original article); began limited use in 2001.
Update of (UOF) cites the article being updated; limited use; began limited use in 2001.
Summary for patients in (SPIN) cites a patient summary article; began use in November 2001 (these records contain Publication Type, Patient Education Handout). See the article 'Patient Education Handouts in MEDLINE®/PubMed®' in the NLM Technical Bulletin at http://www.nlm.nih.gov/pubs/techbull/ma02/ma02_new_pt.html for more information.
Original report in (ORI) cites a scientific article associated with the patient summary.

The PubMed Identifier (PMID) of the associated record in PubMed is provided (if available) to create a link between an article and its commentary.


CIN - N Engl J Med. 2003 Jul 17;349(3):211-2. PMID: 12867604
CON - Dev Cell. 2002 Jul;3(1):85-97. PMID: 12110170
CRI - Orthop Nurs. 2003 May-Jun;22(3):232-9. PMID: 12872752
CRF - Biochemistry. 1994 May 10;33(18):5614-22. PMID: 8180186
EIN - Acta Obstet Gynecol Scand. 2003 Jan;82(1):102
EFR - J Arthroplasty. 2002 Jun;17(4):524-6. PMID: 12066289
RIN - J Biochem Mol Biol. 2002 Nov 30;35(6):642. PMID: 12476908
ROF - Ware FE, Lehrman MA. J Biol Chem. 1996 Jun 14;271(24):13935-8. PMID: 8663248
SPIN- Ann Intern Med. 2003 Jun 3;138(11):I60. PMID: 12779314
ORI - Ann Intern Med. 2003 Jun 3;138(11):907-16. PMID: 12779301
UIN - Cochrane Database Syst Rev. 2002;(3):CD003688. PMID: 12137706
UOF - Cochrane Database Syst Rev. 2002;(2):CD003680. PMID: 12076500

Occasionally, a note is added to the Comment or Correction. The note clarifies the data in the Comments or Correction element. It is most often used with Erratum In for corrected author names. The following are some possible notes:

In records from OLDMEDLINE, Comments In (CIN) is the only Comment or Correction found. Other comment or correction elements may be used in the future.

See the NLM Fact Sheet "Errata, Retraction, Partial Retraction, Corrected and Republished Articles, Duplicate Publication, Comment, Update, Patient Summary and Republished (Reprinted) Article Policy for MEDLINE®" at http://www.nlm.nih.gov/pubs/factsheets/errata.html for additional information.

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Date Completed (DCOM)

Date Completed is the date processing of the record ends; i.e., MeSH® Headings have been added, quality assurance validations are completed, and the completed record subsequently is distributed to PubMed and licensees. This is contrasted with Date Created, which is the date processing begins.



DCOM - 20020207

In Process records lack the Date Completed field. For OLDMEDLINE records, the Date Completed is the approximate date the record entered PubMed, rather than the date processing ends. OLDMEDLINE records are created and processed differently than MEDLINE records.

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Date Created (DA)

Date Created is the date that processing of the record begins.



DA - 20020516

This is contrasted with Date Completed, which is the date processing ends. Date Created is not the same as NLM's PubMed Entrez Date (EDAT), which is the date the record entered PubMed.

For citations up to about the year 2000, the Date Created (DA) and Date Completed (DCOM) data elements are identical. These dates were derived from NLM's legacy ELHILL system.

For OLDMEDLINE citations converted from the 1964 and 1965 Index Medicus (IM), Date Created represents the year and month the citations were printed in the monthly Index Medicus, and the day will always be "01". All other OLDMEDLINE records have a year based on the year of the printed index, the month is always "12" for December, and the day is always "01".

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Date Last Revised (LR)

The Date Last Revised identifies the date a change is made to a record either as a result of individual or global maintenance. There is no indication of what the change is on the record. Only the latest revision date is displayed.



LR - 20020320

When the 10 million+ MEDLINE records through the 2000 production year were converted to XML from NLM's legacy ELHILL system, all records were assigned a Last Revision Date of 20001218 (December 18, 2000). Subsequently, many of these records have been or will be maintained and given a later (LR) date.

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Date of Electronic Publication (DEP)

The Electronic Publication Date is the date the publisher made an electronic version of the article available. In January 2003, global maintenance was performed to add this element retrospectively.



DEP - 20050513

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Date of Publication (DP)

Date of Publication contains the full date on which the issue of the journal was published. The standardized format consists of elements for a 4-digit year, a 3-character abbreviated month, and a 1 or 2-digit day. Every record does not contain all of these elements; the data are taken as they are published in the journal issue, with minor alterations by NLM such as abbreviations.


DP - 2001 Apr 15
DP - 2001 Apr
DP - 2000 Spring
DP - 2000 Nov-Dec
DP - 2001

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Entrez Date (EDAT)

This field contains the date the citation was added to PubMed.



EDAT- 2003/01/02 04:00

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Gene Symbol (GS): not currently input

This field contains the "symbol" or abbreviated form of gene names as reported in the literature. This element resides in records processed at NLM from 1991 through 1995. Up to 25 occurrences per record may appear. NLM entered the symbols used by authors; there was no authority list or effort to standardize the data.


GS - dyrA
GS - cpa2

Greek characters, superscripts, and subscripts may appear as part of the gene symbol. The code designations for the Greek characters may be found at http://www.nlm.nih.gov/bsd/licensee/greek_characters.html.

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General Note (GN)

This field contains supplemental or descriptive information related to the document. The data in this field may be preceded by the acronym for the collaborator who provided this information.

The acronyms and names are:

HMD History of Medicine Division, National Library of Medicine
HSR National Information Center on Health Services Research and Health Care Technology, National Library of Medicine
KIE Kennedy Institute of Ethics, Georgetown University
NASA National Aeronautics and Space Administration
PIP Population Information Program; Johns Hopkins School of Health


GN - KIE: Article and commentaries
GN - KIE: KIE BoB Subject Heading: health care/economics

Note: BoB Subject Headings are controlled subject vocabulary terms found in the Kennedy Institute of Ethics' Bioethics Thesaurus under which citations print in their publication, Bibliography of Bioethics. The current format of these data in MEDLINE is reflected in the second example beginning with "KIE Bob" or "KIE Bib".

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Grant Number (GR)

This field was introduced in 1981 and is comprised of four parts (modified from three in December 2007):

  1. Number contains the research grant or contract number (or both) that designates financial support by any agency of the United States Public Health Service, any institute of the National Institutes of Health, or other agency. The data are generally recorded exactly as they appear in the published article*; there is no attempt to standardize the numbers.
  2. Grant 2-letter code contains the 2-letter grant code or acronym.
  3. Country contains the home country of the granting agency.
  4. Agency includes the institute acronym or mnemonic in the case of US PHS institutes, or full organization name.


GR - LM0577/LM/United States NLM
GR - M0 1 RR01271/RR/United States NIDDK
GR - United Kingdom Wellcome Trust
GR - 058423/United Kingdom Wellcome Trust
GR - 067427/Z/02/Z/United Kingdom Wellcome Trust

A list of the possible values for the grant Acronym and Agency is available from: http://www.nlm.nih.gov/bsd/grant_acronym.html. Please be advised that while NLM enters the grant number, acronym and agency values are derived by using a machine algorithm against the grant number string. This may result in some inaccurate derivations, but the overall benefit of supplying the separate acronym and agency was considered to be worth the risk of some inaccuracies.

Effective for prospective citations indexed with MeSH as of June 2, 2005, the value Wellcome Trust is added if an author acknowledges that the research was supported financially by this organization. Effective March 24, 2006, Wellcome Trust grant numbers may also be added from data entered via PubMed Central, or from the published article. The grant number may appear in either six-digit (e.g., 069355) or expanded (e.g., 067427/Z/02/Z) format.

With the implementation of the United Kingdom Manuscript Submission System in August 2007, NLM began adding data for seven additional United Kingdom granting agencies. In early 2008, Howard Hughes Medical Institute was added as a designated funding organization. The typical data available for Howard Hughes Medical Institute is the name only; grant numbers are not generally part of the information.

Through 1999, NLM entered up to three grant numbers for each record. Beginning in 2000, NLM began to transition to an unlimited number of grant numbers or contract numbers. Some MEDLINE citations from 2000 and 2001 may still be limited to three grant numbers or contract numbers, but beginning in 2002, NLM does not limit the number of grant numbers or contract numbers. Some collaborating partners record grant numbers for agencies outside the U.S. Public Health Service in the General Notes field.

*In July 2006, NLM corrected a large number of NIH grant number prefixes which were entered with the letter O (e.g., RO1) rather than the number 0 (e.g., R01). This practice deviates with NLM's general policy that the data in the online citation match what is in the published article.

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Investigator Name (IR) and Full Investigator Name (FIR)

Beginning in March of the 2008 production year, Investigator Name and Full Investigator Name fields are used to contain personal names of individuals (e.g., collaborators and investigators) who are not authors of a paper but rather are listed in the paper as members of a collective/corporate group that is an author of the paper. The same name listed multiple times will be repeated because NLM cannot make assumptions as to whether those names are the same person.

These fields also reside on MEDLINE citations created or maintained by one of our former collaborating data producers, the National Aeronautics and Space Administration (NASA). They identify the NASA-funded principal investigator(s) who conducted the research discussed in the article cited (but are not necessarily the authors). NASA Investigator Names are associated with the Investigator Affiliation field.

See Author field for details on format. NLM's author indexing policy is explained in the Fact Sheet: Authorship in MEDLINE.


IR - Smith P
FIR - Smith, Paula

IR - Brody BA
FIR - Brody, B A

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ISSN (International Standard Serial Number) is an eight-character value that uniquely identifies the cited journal. It is nine characters long in the hyphenated form: XXXX-XXXX. The ISSN field has a qualifier that follows the ISSN data which will state whether it is for the print or the electronic version ISSN of the journal. For journals with multiple ISSNs (e.g., those with separate ISSNs for the print and electronic versions), the ISSN in the MEDLINE citation reflects the version used for MeSH indexing.


IS - 0021-5252 (Print)
IS - 1471-2202 (Electronic)

Some records do not contain an ISSN value.

The complete title of the journal can be found in the Journal Title (JT) field. See more information about journals cited in MEDLINE.

See also NLM Unique ID (JID).

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Issue (IP)

Issue identifies the issue, part or supplement of the journal in which the article was published.


IP - 11
IP - 7 Pt 1
IP - First Half
IP - 3 Suppl 1

For records from OLDMEDLINE, some records contain Issue but lack Volume; some records contain Volume but lack Issue; and some records contain Volume and Issue data in the Volume element.

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Title (TI)

The title field contains the entire title of the journal article. The title is always in English; those titles originally published in a non-English language and translated for the title field are enclosed in square brackets. All titles end with a period unless another punctuation mark such as a question mark or bracket is present. Explanatory information about the title itself is enclosed in parentheses, e.g.: (author's trans). Corporate/collective authors may appear at the end of the title field for citations up to about the year 2000. See also Corporate Author (CN) for more information about corporate or collective authors.

Records with (In Process Citation) in the title field are non-English language citations in In-Process status that do not yet have the article title translated into English.


TI - The Kleine-Levin syndrome as a neuropsychiatric disorder: a case report.
TI - Why is xenon not more widely used for anaesthesia?
TI - [Biological rhythms and human disease]
TI - [In Process Citation]
TI - Prevalence of Helicobacter pylori resistance to antibiotics in Northeast Italy: a multicentre study. GISU. Interdisciplinary Group for the Study of Ulcer.

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Journal Title Abbreviation (TA)

This field contains the standard abbreviation for the title of the journal in which an article appeared. See the NLM Fact Sheet "Construction of National Library of Medicine Title Abbreviations" at http://www.nlm.nih.gov/pubs/factsheets/constructitle.html, which discusses the rules currently used by the National Library of Medicine (NLM) to construct title abbreviations for journals cited in MEDLINE.


TA - J Pediatr
TA - J Comp Physiol B
TA - Ann Biol Clin (Paris)

The complete title of the journal can be found in the Journal Title (JT) field. See more information about journals cited in MEDLINE.

All MEDLINE/PubMed records must be linked to a parent serial record in NLM's online catalog. In OLDMEDLINE records, the journal title abbreviation may differ from that found on the original citation in the printed index.

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Journal Title (JT)

This field contains the full journal title, taken from NLM's cataloging data following NLM rules for how to compile a serial name. The NLM journal title abbreviation is in the (TA) element.

Examples are:


JT - Molecular microbiology
JT - American journal of physiology. Cell physiology

Some characters that are not part of NLM's MEDLINE/PubMed Character Set reside in a relatively small number of full journal titles. These characters will display as the string 'inverted question mark.'

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Language (LA)

The language in which an article was published is recorded in the Language field. All entries are three letter abbreviations stored in lower case, such as eng, fre, ger, jpn, etc. A record may contain more than one language value. Some records provided by collaborating data producers may contain the value "und" to identify articles whose language is undetermined.


LA - eng
LA - rus

A table listing all languages found in MEDLINE is available at: http://www.nlm.nih.gov/bsd/language_table.html. A chart showing the number of English language MEDLINE articles in various segments of MEDLINE is available at: http://www.nlm.nih.gov/bsd/medline_lang_distr.html.

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Location Identifier (LID)

In April 2008, NLM began accepting LocationID data from publishers for journal citations. This data consists of either a Digital Object Identifier (DOI) or another publisher ID that the publisher has determined serves the role of pagination in a citation in terms of locating the article (PII). This data will be submitted by the publisher in the LocationID field as part of the XML citation. If an LocationID is wrong or changed by the publisher, then the publisher must publish an erratum notice in the journal with the incorrect and correct number in order for NLM to edit the data in the citation.


LID - 8083
LID - s0212 16112008000100001

Note: PubMed records also include PIIs and DOIs in the Article ID field, if it is supplied by the publisher. This field is used to create links for the LinkOut program; it is not used to create citation source information.

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Manuscript Identifier (MID)

A Manuscript ID is an identifier assigned to an author manuscript submitted to the NIH Manuscript Submission System. This may be in support of the NIH Public Access Policy, or another funding agency's policy. The following four types of MIDs currently exist in PubMed records:

NIH Manuscript System (NIHMS)
United Kingdom Manuscript System (UKMS)
Howard Hughes Medical Institute (HHMIMS)
Hyper Articles En Ligne (HAL) from the Centre pour la communication scientifique directe (CCSD)


MID - UKMS1522
MID - HALMS108756

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MeSH Date (MHDA)

The date MeSH terms were added to the citation is recorded in the MeSH Date field. The MeSH date is the same as the Entrez date until MeSH are added.



MHDA- 2005/08/03 09:00

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MeSH Terms (MH)

NLM's controlled vocabulary, Medical Subject Headings (MeSH®), is used to characterize the content of the articles represented by MEDLINE citations.

Of the various MeSH headings assigned to a record, those representing the most significant points are identified with an asterisk (*) in the MeSH display. The remaining descriptors are used to identify concepts that have also been discussed in the item, but that are not the primary topics. In Process and publisher-supplied records lack MeSH terms. See the MeSH Fact Sheet (http://www.nlm.nih.gov/pubs/factsheets/mesh.html) or the MeSH home page (http://www.nlm.nih.gov/mesh/meshhome.html) for additional information about MeSH.

Subheadings (also known as Qualifiers) are often used with MeSH terms to help describe more completely a particular aspect of a subject. Subheadings are displayed after the MH and a slash (/). A major topic asterisk before a subheading indicates when the combination of that subheading with its associated MeSH term is a central concept of the article.

The presentation of MeSH terms is alphabetical. The Subheadings associated with a MeSH term are also in alphabetical order, without regard to the presence of the major topic asterisk (*).

Example 1:

MH - Adult
MH - Cardiovascular Diseases/etiology/*mortality
MH - Child Development/*physiology
MH - Embryo and Fetal Development/*physiology
MH - English Abstract
MH - Fetal Growth Retardation/complications/*physiopathology
MH - Human
MH - Infant, Newborn
MH - Nutrition
MH - Risk Factors
MH - Survival Rate

In the above example, the mortality aspect of cardiovascular diseases, the physiology of child development, as well as embryo and fetal development, and the physiopathology aspect of fetal growth retardation are the central concepts of the article. Note that the MeSH term English Abstract (also present in above example) means that a substantive English language abstract is present in the journal or was written by one of NLM's collaborating data producers. The abstract may or may not be present in the MEDLINE citation as the input policy changed over the years. There are many older non-English language citations without abstracts in MEDLINE but with the MeSH term English Abstract; this indicates that an English abstract is present in the journal, even if not a part of the online record.

Example 2:

MH - Animal
MH - Dogs
MH - *Myocardial Contraction
MH - Myocardium/*metabolism
MH - *Oxygen Consumption
MH - Surface Tension

In the above example, myocardial contraction, the metabolism aspect of myocardium, and oxygen consumption are the central concepts of the article.

The original subject headings assigned to OLDMEDLINE records were updated to current MeSH in December 2005 (with the exception of approximately 8% of OLDMEDLINE records, which will be updated as resources permit). All of the terms assigned to OLDMEDLINE citations are identified as the major topic of the article. The original subject headings have been placed in the Other Term (OT) field.

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NLM Unique ID (JID)

This field is the alpha-numeric identifier for the cited journal. The element's value is the accession number for the journal's record assigned in the NLM Catalog, available at http://www.ncbi.nlm.nih.gov/sites/entrez?db=nlmcatalog or via LocatorPlus at http://locatorplus.gov/. An NLM Unique ID may appear as seven, eight or nine characters.


Citations from the New England Journal of Medicine will have the following JID field value:
JID - 0255562

Citations from the Japanese Journal of Infectious Diseases will have the following JID field value:
JID - 100893704

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Number of References (RF)

This element appears on records indexed with Review as a Publication Type. This field contains the number of bibliographic references listed in the review article.


RF - 21

When collaborating data partners recorded the number of references for non-review articles, these data are found in the General Notes field.

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Other Abstract (OAB)

NLM creates MEDLINE records without an Abstract field when the source journal article does not contain an abstract. In cases where a collaborating data partner provides an abstract, this abstract appears in the Other Abstract field for that record. This field is associated with the Other Copyright Information (OCI) field, which displays beneath (OAB) if present. The abstract included in this field is not written by the authors of the article. The internal tracking number of the source document used by the collaborating partner resides in the Other ID field.

Acronyms used in the OAB field are:
AAMC - American Association of Medical Colleges; not currently used
AIDS - Special HIV/AIDS publications with abstracts written by someone other than the author
KIE - Kennedy Institute of Ethics, Georgetown University
PIP - Population Information Program, Johns Hopkins School of Public Health
NASA - National Aeronautics and Space Administration


OAB - NASA: The purpose of this review is to delineate the ubiquitous and pivotal role of Ca2+ in diverse physiological processes. Emphasis will be given to the role of Ca2+ in stimulus-response coupling. In addition to reviewing the present status of research, our intention is to critically evaluate the existing data and describe the newly developing areas of Ca2+ research in plants.

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Other Copyright Information (OCI)

This field identifies the copyright owner. It appears on some records created by a collaborating data producer if that producer has written the abstract. The information for this field displays beneath the Other Abstract field.


OCI - NASA Edited

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Other ID (OID)

This field may reside on a record owned by a collaborating partner or on an NLM-owned record to which a collaborating partner added additional information. The data identify: a) the organization responsible for the information on the citation or the document where the information originated, and b) a unique number for that citation or document.

The acronyms used in this field are listed below. Some of the values on this list currently are not in use at this time and some may never be used.

NASA National Aeronautics and Space Administration
KIE Kennedy Institute of Ethics, Georgetown University
PIP Population Information Program, Johns Hopkins School of Public Health; not currently used
POP former NLM POPLINE database; not currently used
ARPL Annual Review of Population Law; not currently used
CPC Carolina Population Center; not currently used
IND Population Index; not currently used
CPFH Center for Population and Family Health Library/Information Program; not currently used
NRCBL National Reference Center for Biomedical Literature (for the KIE Reference Library shelving location)
CLML Current List of Medical Literature; reserved for future use
IM Index Medicus; reserved for future use (intended for pre-1966 publications)
QCICL Quarterly Cumulative Index to Current Literature; reserved for future use (intended for pre-1966 publications)
QCIM Quarterly Cumulated Index Medicus; reserved for future use (intended for pre-1966 publications)
SGC Surgeon General's Catalog; reserved for future use

For OLDMEDLINE records, this field occurs on records from 1950-1959 and is for internal use at NLM. CLML is currently the value for all OLDMEDLINE citations containing this field. The value IM may be used on a limited basis. Other values that may be defined for future use with OLDMEDLINE records are QCICL and QCIM.


OID - KIE: 30206
OID - NRCBL: 18.2
OID - CLML: 5834:20412:395

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Other Term (OT)

This field contains largely non-MeSH subject terms (also referred to as Keywords) that describe the content of the article. These are assigned by a collaborating data producer who is identified in the Other Term Owner field. This information is present on a small percentage of citations in the database. The Other Term data may be marked with an asterisk (*) to indicate a major concept. Asterisks are for display only.


OT - Legal Approach
OT - Health Care and Public Health

Other Terms appear in addition to MeSH terms, with the exception of some OLDMEDLINE records which do not yet contain MeSH headings. OLDMEDLINE subject terms were mapped to current MeSH in preparation for NLM's 2006 production year. Both MeSH Headings and Other Terms are on all but approximately 8% of OLDMEDLINE records as of December, 2005. Additional mappings will occur as resources permit.

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Other Term Owner (OTO)

This field contains an acronym that precedes the Other Term field. It identifies the organization that provided the Other Term data. The Other Term Owner acronyms and their respective organizations are:

KIE Kennedy Institute of Ethics, Georgetown University
NASA National Aeronautics and Space Administration
PIP Population Information Program, Johns Hopkins School of Public Health
NLM National Library of Medicine (used for the OLDMEDLINE records)

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Owner (OWN)

The acronym for the organization that supplied the citation data is recorded in this field. Each citation has only one Owner and there are eight possible values in this field:

NLM National Library of Medicine, Index Section
NASA National Aeronautics and Space Administration
PIP Population Information Program, Johns Hopkins School of Public health (not a current value; only on older citations)
KIE Kennedy Institute of Ethics, Georgetown University
HSR National Information Center on Health Services Research and Health Care Technology, National Library of Medicine
HMD History of Medicine Division, National Library of Medicine
SIS Specialized Information Services Division, National Library of Medicine (not yet used; reserved for possible future use)
NOTNLM For licensees' use. Not used by NLM.

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Pagination (PG)

Pagination indicates the inclusive pages for the article cited. The pagination can be entirely non-digit data. Redundant digits are omitted. Document numbers for electronic articles are also found here.


PG - 12-9
PG - 304-10
PG - 335-6
PG - 1199-201
PG - 24-32, 64
PG - suppl 111-2
PG - 564
PG - E101-6
PG - 44; discussion 44-8
PG - 925; author reply 925-6
PG - e66
PG - 10.1-8

Beginning in December 2002, new rules are followed for pagination for letters to the editor that include text consisting of an author reply. If the reply is written by one or more of the authors of the original article, the words "author reply" are used in the pagination field rather than the word "discussion". "Discussion" continues to be used within pagination for other types of articles, such as an article presented at a meeting that is followed by the text of a separate discussion or verbal exchange by a panel or others attending the meeting. This new rule for pagination that includes "author reply" applies only to citations with Publication Type of Letter.

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Personal Name as Subject (PS)

Individuals' names appear in this field for citations that contain a biographical note or obituary, or are entirely about the life or work of an individual or individuals. Data is entered in the same format as author names in the Author field. See Author (AU) field for details of format. See also the associated Full Personal Name as Subject (FPS) field description.


PS - Koop CE
PS - Zerhouni EA

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Full Personal Name as Subject (FPS)

This field contains the full name of the subject of the article for citations with a date of publication beginning with 2002. It is associated with the Personal Name as Subject (PS) field. See details on format in the Full Author (FAU) field description.


FPS - Koop, C Everett
FPS - Zerhouni, Elias Adam

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Place of Publication (PL)

This field indicates the cited journal's country of publication. Valid values are those country names found in the Z category of the Medical Subject Headings (MeSH) that may be displayed from the MeSH Browser at http://www.nlm.nih.gov/cgi/mesh/2008/MB_cgi?term=Geographic+Locations&field=entry#TreeZ01. Values may appear in all upper case or in mixed case. On older records, in cases where the place of publication is unknown, the (PL) value is Unknown.


PL - United States
PL - Nigeria

Place of Publication data are not maintained when names may change over time. These data indicate where the journal is published, not where the research was conducted.

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Publication History Status (PHST)

This field contains information from the publisher regarding important events in the publishing process. It contains a date, and one of the following values for each date in the publication history:

[received] date manuscript received for review
[accepted] accepted for publication
[revised] article revised by publisher or author
[aheadofprint] published electronically, to be followed by the print


PHST- 2004/06/01 [received]
PHST- 2004/09/01 [revised]
PHST- 2005/02/15 [accepted]

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Publication Status (PST)

This field contains the current status of the publication, as submitted by the publisher. Possible values are:

ppublish - published in print (default value)
epublish - electronically published only, never published in print
aheadofprint - electronically published, but followed by print


PST - aheadofprint
PST - ppublish

The date on which the current status took effect is submitted in the Date of Publication field.

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Publication Type (PT)

This field describes the type of material that the article represents; it characterizes the nature of the information or the manner in which it is conveyed (e.g., Review, Letter, Retracted Publication, Clinical Trial). Records may contain more than one Publication Type, which are listed in alphabetical order.


PT - Review
PT - Multicenter Study

A list of the Publication Types is available from PubMed Help at: http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=helppubmed.table.pubmedhelp.T42. A list with definitions is available at http://www.nlm.nih.gov/mesh/pubtypes2008.html. Publication Types are also available in the MeSH Database at http://www.ncbi.nlm.nih.gov/sites/entrez?db=mesh.

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Publishing Model (PUBM)

This field describes the medium/media in which the cited article is published. This information is derived from data submitted by the publishers.


PUBM - Print
PUBM - Print-Electronic

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PubMed Central Identifer (PMC)

This field contains the unique identifer for the cited article in PubMed Central. The identifier begins with the prefix PMC.


PMC - PMC1463022
PMC - PMC2271135

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PubMed Unique Identifier (PMID)

This field is a 1- to 8-digit accession number with no leading zeros. It is present on all records and is the accession number for managing and disseminating records. PMIDs are not reused after records are deleted.


PMID - 10097079
PMID - 6012557

Prior to the 2004 version of PubMed (available December 3, 2003), many records contained a MEDLINE Unique Identifier in addition to the PMID. NLM no longer displays the MEDLINE Unique Identifier. The PMID has become the unique identifier for the MEDLINE record.

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Registry Number/EC Number (RN)

This field contains the unique 5- to 9-digit number in hyphenated format assigned by the Chemical Abstracts Service (CAS) to specific chemical substances. For enzymes, the EC number derived from Enzyme Nomenclature is placed in this element. A zero (0) is a valid value when an actual number cannot be located or is not yet available.

Following the RN/EC field display is the Substance Name (NM) field value, enclosed in parentheses. Please see Substance Name (NM) field section for an explanation of that field.


RN - 69-93-2 (Uric Acid)
RN - EC (Lipoprotein Lipase)

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Substance Name (NM)

This field contains the name of the substance that the registry number or the EC number identifies. The MeSH Database (http://www.ncbi.nlm.nih.gov/sites/entrez?db=mesh) or MeSH Browser (http://www.nlm.nih.gov/mesh/MBrowser.html) contain the Substance Names. These records are of two types: 1) Supplementary Concept Records, which can be found in the MeSH Browser with a record type of C, or 2) MeSH Category D descriptors, identified in the MeSH Browser with a tree number that begins with D. The Substance Name follows the RN/EC field display, enclosed within parentheses.


RN - 69-93-2 (Uric Acid)
RN - 6964-20-1 (tiadenol)

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Secondary Source ID (SI)

The SI field contains information pertaining to the registration of several types of data discussed in MEDLINE articles: a) molecular sequence data; b) gene expression/molecular abundance data (beginning February 2006); c) clinical trial numbers (beginning summer 2005); and d) PubChem identifiers. The field is composed of the source followed by a slash followed by an accession number.


SI - ClinicalTrials.gov/NCT00000419
SI - PubChem-Substance/17424970

Molecular Sequence Data

NLM cooperates with international efforts to collect molecular sequence data. There are, at present, seven databanks that register molecular sequences deposited with them by researchers. In the journal literature, a reference to the databank and the accession number assigned to the sequence may accompany, or substitute for, a lengthy graphic representation of the sequence itself. NLM enters this data in the SI field if this information appears in the printed journal article. If the article lists a databank but no accession number, only the abbreviation for the databank will be entered. There is no attempt to edit or verify the databank accession numbers that appear in the journal. Since sequences may be deposited with more than one databank, there may be multiple occurrences of this field in a single citation. This information may appear on the article title page, in a footnote or in a statement such as:

Sequence data from this article have been deposited with the EMBL, GenBank and DDBJ Data Libraries under Accession No. M16978.

The seven databanks registering molecular sequence data at the present time are:

MEDLINE Abbreviation Databank
GDB Johns Hopkins University Genome Data Bank
GENBANK GenBank Nucleic Acid Sequence Database
OMIM Mendelian Inheritance in Man (McKusick)
PDB Protein Data Bank
PIR Protein Identification Resource
RefSeq Reference Sequence
SWISSPROT Protein Sequence Database

NLM first began to include this information with the 1988 indexing year. Prior to 2000, NLM's policy was to enter up to 30 databank accession numbers for each record. Some global maintenance was done over the years to add databank names/accession numbers whether or not the article itself contained those references. From 2000 forward, NLM enters all databank accession numbers published in the journal. Data in this field are sorted first by databank name and then by the accession number.

Beginning in September 2006, accession numbers for sequences in NLM's Reference Sequence (RefSeq) database are included in the SI field. RefSeq is a curated, non-redundant set of sequences, including genomic DNA, transcript RNA and protein products.

The SI field and the Entrez sequence database links are not related. The PubMed links to these databases are created from the reference field of the GenBank or GenPept flatfile. These references include citations that discuss the specific sequence presented in these flatfiles.

Gene Expression Data

Beginning in February 2006, accession numbers for data deposited in NLM’s Gene Expression Omnibus (GEO) database are included in SI field. GEO is a gene expression/molecular abundance repository supporting data submissions, and a curated, online resource for gene expression data browsing, query and retrieval.

The databank abbreviation is GEO and the accession number is any one of four prefixes followed by a numeric string:

GDSxxxx (GEO Data Set)
GSExxxx (GEO SEries)
GPLxxxx (GEO PLatform)
GSMxxxx (GEO SaMple)

Clinical Trial Numbers

Beginning in the Summer of 2005, NLM includes the ClinicalTrials.gov identifier number in the SI field when the article is devoted solely and entirely to announcing or reporting the results of the clinical trial. The ICMJE Web site (http://www.icmje.org/) contains an editorial and updates on the topic of registering clinical trials before publication of the results.

Beginning mid-2006, MEDLINE citations also carry the International Standard Randomised Controlled Trial Number (ISRCTN) when when the article is devoted solely and entirely to announcing or reporting the results of the clinical trial or other study that the Identifier Number represents. The ISRCTN Register (http://isrctn.org/) is a clinical trials deposit site based in the UK that meets the criteria set forth by the ICMJE (International Committee of Medical Journal Editors) for responsible disclosure of information to the public. The letters ISRCTN are a part of the trial number.

PubChem Identifiers

Beginning in January 2007, identifiers for records in the PubChem Substance database may be included in the SI field (but only if the data are included in the citation XML feeds from the publishers). The abbreviation is PubChem-Substance and the accession number is a numeric string, e.g. 10318689. In the distant future, identifiers for records in two additional databases, PubChem Compound and PubChem BioAssay, will likely also be added to MEDLINE/PubMed records.

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Source (SO)

NLM concatenates the following elements to create the journal source:

Journal Title Abbreviation (TA)
Publication Date (DP)
Volume (VI)
Issue (IP)
Pagination (PG)

Elements of other date fields may be added to indicate an additional Epub or Print publication date.


SO - Am J Med. 2005 May;118(5):567.
SO - Hepatology. 2004 Apr;39(4):915-23.
SO - Health Care Finance Rev. 2003 Winter;25(2):77-90.
SO - Eur Spine J. 2005 Nov;14(9):887-94. Epub 2005 Sep 8.

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Space Flight Mission (SFM)

This field resides on citations created by one of our collaborating data producers, the National Aeronautics and Space Administration (NASA). It is the space flight/mission name and/or number when results of research conducted in space are covered in the cited publication. View a complete list of Space Flight Missions and their associated values (manned/unmanned; short/long duration) at http://www.nlm.nih.gov/bsd/space_flight.html.


SFM - Flight Experiment
SFM - Mir Project
SFM - long duration
SFM - manned

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Status (STAT)

The status field indicates the status of the record. There are seven possible values for this field:

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Subset (SB)

This field identifies the subset for MEDLINE records from certain journal lists or records on specialized topics. Some of these values are found on extremely small numbers of records. Citations may contain more than one occurrence of this field. The value is true at the time the record was created. If the status of a journal changes, the value on the record does not change.

Subset field values and their definitions are as follows. Note that several are closed subsets no longer being assigned.

AIM citations from Abridged Index Medicus journals, a list of about 120 core clinical, English language journals.
B citations from non-Index Medicus journals in the field of biotechnology (not currently used).
C citations from non-Index Medicus journals in the field of communication disorders (not currently used).
D citations from dental journals. See the current List of Journals Indexed for MEDLINE (LJI) under Dentistry and Orthodontics.
E citations in the field of bioethics. (includes records from the former BIOETHICSLINE database)
F older citations from one journal prior to its selection for Index Medicus. Used to augment the database for NLM's International MEDLARS Centers (not currently used).
H citations from non-Index Medicus journals in the field of health administration. (includes records from the former HealthSTAR database)
IM citations from Index Medicus journals.
J citations in the field of population information. (not currently used; on records from the former POPLINE® database)
K citations from non-Index Medicus journals relating to consumer health.
N citations from nursing journals. See the current List of Journals Indexed for MEDLINE (LJI) under Nursing.
OM citations from the OLDMEDLINE project that originated from the Cumulated Index Medicus and the Current List of Medical Literature (in 2008 this includes citations from the 1949-1965 print indexes). The ways they differ from other MEDLINE records are documented under the applicable element descriptions. The original MeSH Headings assigned at the time the citation was created in print reside in the Other Term field. Records in the OLDMEDLINE subset have a status of OLDMEDLINE until all of their original subject terms are mapped to current MeSH; then their status changes to MEDLINE. NLM makes available both new and revised OLDMEDLINE records on an irregular and infrequent basis.
Q citations in the field of the history of medicine. (includes records from the former HISTLINE® database)
QIS citations from non-Index Medicus journals in the field of the history of medicine. (For NLM use effective in late 2006 because they require special handling at NLM; not a subset of Q; some journals previously designated as Q are now QIS.)
QO is subset of Q - indicates older history of medicine journal citations that were created before the former HISTLINE file was converted to a MEDLINE-like format. (For NLM use because they require special handling at NLM).
R citations from non-Index Medicus journals in the field of population and reproduction (not currently used).
S citations in the field of space life sciences. (includes records from the former SPACELINE™ database)
T citations from non-Index Medicus journals in the field of health technology assessment. (includes records from the former HealthSTAR database)
X citations in the field of AIDS/HIV. (includes records from the former AIDSLINE® database)


SB - X

Do not confuse these journal/citation subsets with the Topics subsets available on PubMed's Limits screen, which are search strategies.

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Transliterated Title (TT)

This field contains the title of each item originally published in a non-English language, in that language. Transliterations of article titles in some Cyrillic languages (Greek, Bulgarian, Russian, Serbian and Ukrainian) were added to this field through 2004.


TT - Temoignages et lettres.
TT - Wplyw przebiegu rozwoju plodu i noworodka na ujawnienie sie niektórych chorób okresu doroslego.

For OLDMEDLINE records, the TT field for citations from the 1964 and 1965 Cumulated Index Medicus (CIM) is in all uppercase letters. Some OLDMEDLINE citations to articles originally published in a non-English language lack the TT field.

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Volume (VI)

The volume number of the journal in which the article was published is recorded here.


VI - 7
VI - 5 Spec No
VI - 49 Suppl 20

Some records (especially records from OLDMEDLINE) contain the Issue field but lack the Volume field; some contain the Volume field but lack the Issue field; and some records contain Volume and Issue data in the Volume element.

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Last reviewed: 12 September 2008
Last updated: 12 September 2008
First published: 17 May 2005
Metadata| Permanence level: Permanent: Dynamic Content