[Occult blood in stool. A field trial in cancer screening (author's transl)].

4000 male probands aged 45 to 69 were investigated in a field trial according to random distribution for undetected intestinal bleeding with the Haemoccult - method. With a participation of 28% only 39 out of a total of 65 positive cases could be evaluated. Four cases of colon or rectal carcinoma and four cases of colonic polyps were ascertained. In view of complete lack of experience with false negative test results the Haemoccult test is at present a useful addition to the diagnostic possibilities. However, in suspected cases even a repeatedly negative test cannot replace complete colo-rectal investigation.