Fecal Immunochemical Tests for Colorectal Cancer Screening New fecal occult blood tests have a higher sensitivity and specificity for detection of adenomas and cancer than guaiac-based tests.

摘要

Until recently, using a stool-based test to screen for colorectal cancer meant using a guaiac-based test.Guaiac-based tests identify the presence of blood in the stool by detecting the peroxidase activity of the heme molecule in hemoglobin.8 However, these tests are not specific for human blood and can produce false-positive results when red meat (which contains heme) or fruits and vegetables containing peroxidase are eaten in the days preceding a guaiac-based test.Moreover, bleeding in the upper gastrointestinal tract from use of nonsteroidal antiinflammatory drugs, or high doses of vitamin C within days of testing, may cause false negatives.