Cancer Care Ontario guaiac fecal occult blood test (FOBT) laboratory standards: evidentiary base and recommendations.

OBJECTIVES

To evaluate the evidence concerning gFOBT kits and to develop gFOBT standards to be implemented by the Ontario Colorectal Cancer (CRC) Screening Program (the "Program").

DESIGN AND METHODS

We evaluated 3 aspects of gFOBT kits: 1) performance factors; 2) usability factors; and 3) laboratory factors. We obtained information from the published literature, other countries that use gFOBT, the internet, and gFOBT kit manufacturers' instructions.

RESULTS

The Program should use a single brand of gFOBT kit with sensitivity > or =40% and specificity > or =95% for the detection of CRC in repeated testing. The Program should regularly monitor gFOBT performance. Participants should not restrict their diets except for eliminating vitamin C supplements and citrus fruits and juices for 3 days prior to and during stool collection; participants should not discontinue taking aspirin (ASA) or non-steroidal anti-inflammatory drugs (NSAIDs). The Program should use one or a limited number of labs; leak-proof envelopes should be used that protect samples during mailing; the lab should delay processing fecal samples for at least 48 h following stool collection; the lab should implement staff training and quality control protocols.

CONCLUSIONS

The Program should monitor and report on its performance according to these standards, and should continually assess new evidence related to CRC screening methods.