Help - ClinicalTrials.gov

On the Basic Search page, enter a word or word(s) that you want to use to find studies. These may include diseases, interventions, and/or locations.

Medical terms are often several words long, such as Percutaneous Coronary Intervention. To only find studies where the words are together as a phrase, put the term in quotes (e.g., "Percutaneous Coronary Intervention"). If you search for a multi-word term without quotes, studies with all words together as a phrase will appear higher in the results list than studies where the words are separated and spread throughout the document. For example, a search for Heart Attack will list a study about,

Use of a Pacemaker Following a Heart Attack.

higher than the study,

Heart Defects and Transient Ischemic Attacks

A search for "Heart Attack" would not find the second study. Synonyms are known for some terms and are used where possible. For example, a search for Heart Attack will also find occurrences of Myocardial Infarction.

Many searches are a single term and can be performed with a few words in the search box. But, sometimes you need more control. Click on the Advanced Search tab (if starting a new search) or Refine Search tab (if modifying an existing search) to show additional search fields.

The additional search fields can be used to limit your search results. Note that it is not necessary to fill in all the fields, only those that are needed for your search. If you are finding too few studies, consider clearing a field and searching again.

Search Terms:

Performs a general search in all sections of the study record, including title, description, conditions, interventions, locations, etc. Terms in this field are searched the same as Basic Search.

Recruitment:

Limits search results to studies that are open or closed. New volunteers may be able to participate in open studies, but not closed studies.

Open recruitment status values:

Recruiting,
Not yet recruiting, or
Available for expanded access.

Closed recruitment status values:

Active, not recruiting,
Completed,
Terminated,
Suspended,
Withdrawn,
Enrolling by invitation,
Temporarily not available for expanded access,
No longer available for expanded access, or
Approved for marketing.

Values are color coded (as shown) in the search results.

Study Results:

Limits search results based on whether the study has results or not:

All Studies,
Studies With Results, or
Studies Without Results

The inclusion of Study Results is a new feature of ClinicalTrials.gov. Only a few studies have results available.

Study Type:

Limits search results to any of the following study types:

Interventional,
Observational, or
Expanded Access

Conditions:

Performs a search on fields describing the diseases or conditions being studied.

Interventions:

Performs a search on fields listing the drugs or interventions being studied.

Sponsors:

Performs a search on fields listing the sponsors of a study.

When the Exact checkbox is checked, the sponsor name in the study must exactly match the sponsor name in the search. For example, if unchecked, a search for Merck in the sponsor field will find Merck, Merck KGaA, Dupont Merck, and Merck Sharp & Dohme. When checked, only Merck, with no other words in the name, will be found.

Study IDs:

Performs a search on fields listing ID numbers.

Country/State:

Trials are often conducted at many locations around the world. Select up to three locations to find trials conducted in specific countries. Some countries (currently limited to the United States, Canada, and Australia), locations can be narrowed further by selecting a state (e.g., United States, Alabama).

Location Terms:

Finds studies in specific locations such as a city (Los Angeles) or facility (Mayo Clinic). Not all studies include this level of detail, but if they do, this will find them.

Age Group:

Limits search results to those studies that include at least one of the specified age ranges. More than one age group can be selected.

Phase:

Limits search results to studies that are labeled with at least one of the specified phases. More than one Phase can be selected.

Funded By:

Limits search results to studies that have at least one sponsor of the specified types. More than one sponsor type can be selected.

First Received:

Limits search results to studies that were received by ClinicalTrials.gov within a specified date range. The "From" or "To" field can be left blank.

Last Updated:

Limits search results to studies that were modified within a specified date range. The "From" or "To" field can be left blank.

Searches display a list of studies found (List Results tab). If you are not content with the search results, click on the Refine Search tab at the top of the list to modify your search.

Add terms to empty fields to search within your current result. You can also add terms to fields that contain terms. For best results, use an AND (all upper case) as a separator between terms in the same field.

For example:

heart attack
heart attack AND aspirin
heart attack AND aspirin AND older adults
heart attack AND aspirin AND older adults AND California

When you are done making changes, click Search to display the new results.

Use AND (all upper case) to find study records that contain all terms connected by AND.
For example:

prostate cancer AND radiation
heart disease AND stroke AND California

Use OR (all upper case) to find study records that contain either term connected by OR.
For example:

Aspirin OR ibuprofen
heart disease OR heart attack

Use NOT (all upper case) to find study records that do not contain the term following NOT.
For example:

Immunodeficiency NOT AIDS

Likewise, AND, OR, NOT, and parentheses can be used to create more complicated search expressions.
For example:

prostate cancer AND NOT ( radiation OR homeopathic remedies )
( heart disease OR heart attack ) AND ( stroke OR clot )

Note that the use of AND and OR as logical operators can be confusing.
An appropriate search for a list such as,

Ear, Nose, and Throat Conditions

is the expression

( Ear OR Nose OR Throat ) AND Conditions

Fortunately, search will do a pretty good job of finding the right studies either way.

To search for AND as a word, instead of using it as an operator, put it in quotes.
Likewise, you can quote OR, NOT, and parentheses.