title: Immunochemical detection of fecal occult blood--the fecal smear punch-disc test: a new non-invasive screening test for colorectal cancer.
abstract: An immunochemical test for fecal occult blood was developed for use in colon cancer screening. The test employs high titer monospecific antisera to intact human hemoglobin in a radial immunodiffusion assay. Patient smears on specially treated filter paper allow screening procedures similar to those using Hemoccult slides. Minimum detectible hemoglobin was 0.3 mg/gm stool, and no cross reactivity with dietary constituents, drugs, or chemicals occurred. The accession of 150 consecutive cases of colon-rectal carcinoma was accomplished from three community hospitals. In each instance, at least one preoperative fecal specimen was obtained for companion smear testing with immunochemical punch-disc and commercial Hemoccult slides. Twenty-nine percent of the cases were found not to be bleeding by either test. Occult bleeding was detected by Hemoccult in 40% of the cases, and occult bleeding was detected by immunochemical testing in 65% of the cases. A surprising discovery was that rectal lesions had a much lower rate of of positiuity with both tests (Hemoccult-29%, Immunochemical-50%) than other locations. These results suggest that immunochemical screening for occult blood loss will provide a higher rate of detection of colon cancer.
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000517:prevention & control*; D003951:Diagnostic Errors; D005243:Feces / Q000032:analysis*; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis; D006801:Humans; D007120:Immunochemistry; D008403:Mass Screening / Q000379:methods*; D009780:Occult Blood; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000517:prevention & control*