Fecal alpha 1-antitrypsin detection of colorectal neoplasia. An evaluation using HemoQuant.

Fecal alpha 1-antitrypsin measurement may be of value for the detection of colorectal neoplasia and is compared with the HemoQuant test in 119 subjects with either a screen-positive Hemoccult result (N = 78) or iron-deficiency anaemia (N = 41). Nineteen patients were found to have colorectal cancer, 35 had colorectal adenomatous polyps, 5 had inflammatory bowel disease, and 60 had no detected cause of occult blood loss. Of the cancer patients, 63% (12/19) were detected by fecal alpha 1-antitrypsin and 63% (12/19) by HemoQuant. Of the adenomas > 1 cm in diameter 33% (7/23) were detected by fecal alpha 1-antitrypsin and 26% (6/23) by HemoQuant. There was a poor correlation between fecal alpha 1-antitrypsin and HemoQuant results for colorectal cancers (r = 0.37, P > 0.05), and combining the tests, the sensitivity for colorectal cancer was increased to 84% (16/19). Fecal protein loss, as measured using alpha 1-antitrypsin, appears to involve largely different mechanisms from that of blood loss from colorectal cancers.