Gastrointestinal (GI) bleeding can be a common cause of hospitalization, particularly in elderly patients.¹ GI bleeding can be overt (where the patient and physician can detect the presence of blood without testing), occult (where there are symptoms of bleeding such as anemia, but that a test is needed to confirm bleeding), or obscure (where the bleeding or source of bleeding is not identified despite invasive testing).² Occult bleeding is often caused by colorectal cancer (CRC) lesions whereas other bleeding could be caused by small bowel diseases or upper GI conditions.^1,3

One commonly accepted method to screen for CRC is the fecal occult blood test (FOBT).⁴ FOBT may be guaiac-based (gFOBT) or immunochemical (iFOBT or FIT). Guaiac-based FOBT detects hemoglobin by the presence of a peroxidase reaction. Immunochemical tests use antibodies to detect the globulin portion of human hemoglobin.⁵ FOBT is known to be effective in detecting colorectal lesions³ by identifying occult blood in the stool. It is not well known, however, whether or not FOBT is effective in identifying other gastrointestinal bleeding.³ In fact, FOBT is validated for use in asymptomatic patients for CRC screening and has generally not been recommended for use in symptomatic patients.⁶ Despite being generally recommended for screening use, a survey of Canadian gastroenterologists and specialists in the Winnipeg Regional Health Authority showed that FOBT was commonly ordered in hospitalized patients with black stools and anemia with or without iron deficiency.⁷

This review seeks to determine the clinical effectiveness of urgent non-screening FOBT for hospitalized patients with suspected GI bleeding and to identify relevant evidence-based guidelines for the use of FOBT in those patients.

Contents

• CONTEXT AND POLICY ISSUES
• RESEARCH QUESTIONS
• KEY FINDINGS
• METHODS
  • Literature Search Methods
  • Selection Criteria and Methods
  • Exclusion Criteria
  • Critical Appraisal of Individual Studies
• SUMMARY OF EVIDENCE
  • Quantity of Research Available
  • Summary of Study Characteristics
  • Summary of Critical Appraisal
  • Summary of Findings
  • Limitations
• CONCLUSIONS AND IMPLICATIONS FOR DECISION OR POLICY MAKING
• REFERENCES
• APPENDIX 1. Selection of Included Studies
• APPENDIX 2. Characteristics of Included Publications
• APPENDIX 3. Critical Appraisal of Included Publications
• APPENDIX 4. Main Study Findings and Author’s Conclusions

Disclaimer: The Rapid Response Service is an information service for those involved in planning and providing health care in Canada. Rapid responses are based on a limited literature search and are not comprehensive, systematic reviews. The intent is to provide a list of sources of the best evidence on the topic that the Canadian Agency for Drugs and Technologies in Health (CADTH) could identify using all reasonable efforts within the time allowed. Rapid responses should be considered along with other types of information and health care considerations. The information included in this response is not intended to replace professional medical advice, nor should it be construed as a recommendation for or against the use of a particular health technology. Readers are also cautioned that a lack of good quality evidence does not necessarily mean a lack of effectiveness particularly in the case of new and emerging health technologies, for which little information can be found, but which may in future prove to be effective. While CADTH has taken care in the preparation of the report to ensure that its contents are accurate, complete and up to date, CADTH does not make any guarantee to that effect. CADTH is not liable for any loss or damages resulting from use of the information in the report.