• Foran Melanson S, Petersen J, Lewandrowski KB. Occult blood. In: Laboratory medicine practice guidelines: evidence-based practice for point-of-care testing. Washington (DC): National Academy of Clinical Biochemistry (NACB); 2006. p. 95-104. [75 references]

This is the current release of the guideline.

• Colorectal cancer (CRC)
• Gastric cancer
• Other causes of gastrointestinal bleeding

Prevention
Screening
Technology Assessment

Emergency Medicine
Family Practice
Gastroenterology
Geriatrics
Internal Medicine
Oncology
Preventive Medicine

Advanced Practice Nurses
Allied Health Personnel
Clinical Laboratory Personnel
Health Care Providers
Hospitals
Nurses
Physician Assistants
Physicians
Public Health Departments

• To examine the application of evidence-based medicine (EBM) to the form of diagnostic testing known as point-of-care testing (POCT)

  Note: For the purpose of this document, POCT is defined as "clinical laboratory testing conducted close to the site of patient care, typically by clinical personnel whose primary training is not in the clinical laboratory sciences or by patients (self-testing). POCT refers to any testing performed outside of the traditional, core or central laboratory."

• To systematically review and synthesize the available evidence on the effectiveness of POCT, with specific focus on outcomes in the areas of:
  1. Patient/health
  2. Operational/management
  3. Economic benefit
• To summarize the review of the literature on fecal occult blood and gastric occult blood and to address the use of fecal occult blood tests (FOBT) for detecting colorectal neoplasia and other gastrointestinal lesions, as well as to review data concerning the preferred methodology for FOBT in outpatient and inpatient settings

• Asymptomatic individuals older than 50 years
• Patients with gastrointestinal bleeding

Annual or biennial guaiac-based fecal occult blood testing (FOBT) (in average risk, asymptomatic men and women beginning at age 50 to reduce mortality from colorectal cancer [CRC])

Note: The following interventions were considered but not recommended: FOBT in asymptomatic population to reduce the incidence of CRC, FOBT in symptomatic patients to differentiate bleeding caused by upper gastrointestinal lesions from bleeding caused by lower gastrointestinal lesions, FOBT in patients receiving anticoagulation to predict the risk of gastrointestinal bleeding, and Gastroccult testing of gastric fluid in intensive care unit patients receiving antacid prophylaxis.

• Patient outcomes such as incidence of colorectal cancer (CRC) and mortality rate from CRC
• Sensitivity, specificity, and positive predictive value of various fecal occult blood test (FOBT) methods
• Utility of FOBT in combination with sigmoidoscopy

Hand-searches of Published Literature (Primary Sources)
Searches of Electronic Databases

For a specific clinical use, pertinent clinical questions were formulated and key search terms were ascertained for the literature search. Searches were conducted on MEDLINE or PubMed and were supplemented with the use of the National Guideline Clearinghouse, the Cochrane Group, or evidence-based medicine (EBM) reviews. Additionally, authors' personal article collections were used. Acceptable citations were limited to peer-reviewed articles with abstracts, those published in English, and those involving human subjects.

To be included in the full systematic review of the clinical question, articles selected for full text review were examined for at least 1 relevant outcomes measurement.

The literature search performed for occult blood testing is seen in Literature Search 61 in Appendix B (see the "Availability of Companion Documents" field).

Not stated

Weighting According to a Rating Scheme (Scheme Given)

Levels of Evidence

1. Evidence includes consistent results from well-designed, well-conducted studies in representative populations.
2. Evidence is sufficient to determine effects, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies; generalizability to routine practice; or indirect nature of the evidence.
3. Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information.

Review of Published Meta-Analyses
Systematic Review with Evidence Tables

Abstracts identified by the literature searches were reviewed by 2 individuals to determine initial eligibility or ineligibility for full-text review, using Form 1 (Appendix A - see the "Availability of Companion Documents" field). If there was not consensus, then a third individual reviewed the abstract(s). To be included in the full systematic review of the clinical question, articles selected for full text review were examined for at least 1 relevant outcomes measurement. The systematic review consisted of creating evidence tables using Form 2 (Appendix A - see the "Availability of Companion Documents" field) that incorporated the following characteristics:

1. Study design—Prospective or retrospective, randomized, and controlled, patient inclusion/exclusion criteria, blinding, number of subjects, etc.
2. Appropriateness of controls
3. Potential for bias (consecutive or nonconsecutive enrollment)
4. Depth of method description—full-length report or technical brief
5. Clinical application—screening, diagnosis, management
6. Specific key outcomes and how they were measured
7. Conclusions are logically supported

For the assessment of study quality, the general approach to grading evidence developed by the US Preventive Services Task Force was applied (see the "Rating Scheme for the Strength of the Evidence" field). Once that was done, an assessment of study quality was performed, looking at the individual and aggregate data at 3 different levels using Forms 3 and 4 (Appendix A - see the "Availability of Companion Documents" field). At the first level, the individual study design was evaluated, as well as internal and external validity. Internal validity is the degree to which the study provides valid evidence for the populations and setting in which it was conducted. External validity is the extent to which the evidence is relevant and can be generalized to populations and conditions of other patient populations and point-of-care testing (POCT) settings.

The synthesis of the volume of literature constitutes the second level, Form 5 (Appendix A - see the "Availability of Companion Documents" field). Aggregate internal and external validity was evaluated, as well as the coherence/consistency of the body of data. How well does the evidence fit together in an understandable model of how POCT leads to improved clinical outcome? Ultimately, the weight of the evidence about the linkage of POCT to outcomes is determined by assessing the degree to which the various bodies of evidence (linkages) "fit" together. To what degree is the testing in the same population and condition in the various linkages? Is the evidence that connects POCT to outcome direct or indirect? Evidence is direct when a single linkage exists but is indirect when multiple linkages are required to reach the same conclusion.

Expert Consensus

The field of point-of-care testing (POCT), diagnostic testing conducted close to the site of patient care, was divided into disease- and test-specific focus areas. Groups of expert physicians, laboratorians, and diagnostic manufacturers in each focus area were assembled to conduct systematic reviews of the scientific literature and prepare guidelines based on the strength of scientific evidence linking the use of POCT to patient outcome.

Final guidelines were made according to Agency for Healthcare Research and Quality (AHRQ) classification (see the Rating Scheme for the Strength of the Recommendations field). The guidelines are evidence based and require scientific evidence that the recipients of POCT experience better health outcomes than those who did not and that the benefits are large enough to outweigh the risks. Consensus documents are not research evidence and represent guidelines for clinical practice, and inclusion of consensus documents was based on the linkages to outcomes, the reputation of the peer organization, and the consensus process used to develop the document. Health outcomes, e.g., benefit/harm, are the most significant outcomes in weighing the evidence and drafting guidelines.

Strength of Recommendations

A - The National Academy of Clinical Biochemistry (NACB) strongly recommends adoption; there is good evidence that it improves important health outcomes and concludes that benefits substantially outweigh harms.

B - The NACB recommends adoption; there is at least fair evidence that it improves important health outcomes and concludes that benefits outweigh harms.

C - The NACB recommends against adoption; there is evidence that it is ineffective or that harms outweigh benefits.

I - The NACB concludes that the evidence is insufficient to make recommendations; evidence that it is effective is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.

The guideline developers reviewed published cost analyses (see original guideline document for details).

Peer Review

The guidelines were presented in open forum at the American Association for Clinical Chemistry (AACC) Annual Meeting (Los Angeles, CA, USA) in July 2004. Portions of these guidelines were also presented at several meetings between 2003 and 2005. Participants at each meeting had the ability to discuss the merits of the guidelines and submit comments to the National Academy of Clinical Biochemistry (NACB) Web site for formal response by the NACB during the open comment period from January 2004 through October 2005.

None provided

The type of supporting evidence is identified and graded for each recommendation (see "Major Recommendations").

• It is hoped that these guidelines will be useful for those implementing new testing, as well as those reviewing the basis of current practice. These guidelines should help sort fact from conjecture when testing is applied to different patient populations and establish proven applications from off-label and alternative uses of point-of-care testing (POCT). These guidelines will also be useful in defining mechanisms for optimizing patient outcome and identify areas lacking in the current literature that are needed for future research.
• Annual or biennial guaiac-based fecal occult blood test (FOBT) in asymptomatic individuals older than 50 years have shown a 15% to 33% reduction in mortality from colorectal cancer.

Fecal occult blood test (FOBT) can render false-positive or false negative results.

• The material in this monograph represents the opinions of the editors and does not represent the official position of the National Academy of Clinical Biochemistry or any of the cosponsoring organizations.
• Point-of-care testing (POCT) is an expanding delivery option because of increased pressure for faster results. However, POCT should not be used as a core laboratory replacement in all patient populations without consideration of the test limitations and evaluation of the effect of a faster result on patient care.

An implementation strategy was not provided.

Getting Better
Staying Healthy

Effectiveness

• Foran Melanson S, Petersen J, Lewandrowski KB. Occult blood. In: Laboratory medicine practice guidelines: evidence-based practice for point-of-care testing. Washington (DC): National Academy of Clinical Biochemistry (NACB); 2006. p. 95-104. [75 references]

Not applicable: The guideline was not adapted from another source.

2006

National Academy of Clinical Biochemistry - Professional Association

National Academy of Clinical Biochemistry

Guidelines Committee

Committee Members: Robert H. Christenson, Ph.D., FACB, University of Maryland School of Medicine, Baltimore, Maryland, USA; William Clarke, Ph.D., Johns Hopkins Medical Institutions, Baltimore, Maryland, USA; Ann Gronowski, Ph.D., FACB, Washington University, St. Louis, Missouri, USA; Catherine A. Hammett-Stabler, Ph.D., FACB, University of North Carolina Chapel Hill, Chapel Hill, North Carolina, USA; Ellis Jacobs, Ph.D., FACB, New York State Department of Health, Albany, New York, USA; Steve Kazmierczak, Ph.D., FACB, Oregon Health and Science University, Portland, Oregon, USA; Kent Lewandrowski, M.D., Massachusetts General Hospital, Boston, Massachusetts, USA; Christopher Price, Ph.D., FACB, University of Oxford, Oxford, UK; David Sacks, M.D., FACB, Brigham and Women's Hospital, Boston, Massachusetts, USA; Robert Sautter, Ph.D., Carolinas Medical Center, Charlotte, North Carolina, USA; Greg Shipp, M.D., Nanosphere, Northbrook, Illinois, USA; Lori Sokoll, Ph.D., FACB, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA; Ian Watson, Ph.D., FACB, University Hospital Aintree, Liverpool, UK; William Winter, M.D., FACB, University of Florida, Gainesville, Florida, USA; Marcia L. Zucker, Ph.D., FACB, International Technidyne Corporation (ITC), Edison, New Jersey, USA

Not stated

This is the current release of the guideline.

None available

This NGC summary was completed by ECRI Institute on August 13, 2007. The information was verified by the guideline developer on September 24, 2007.

National Academy of Clinical Biochemistry's (NACB) terms for reproduction of guidelines are posted with each set of guidelines.