[The value of determining occult blood in clinical practice].

The haemoccult-test is recommended above all for the early recognition of the colon carcinoma. The stool of 183 relatively unselected patients was examined for occult blood by means of this test in order to control its importance for clinical practice. In 37 patients (20%) the test was positive at least once. Apart from origins of haemorrhage in the lower gastrointestinal tract in the upper one haemorrhages were found in epistaxis, hiatal hernia, gastric and duodenal ulcers [7] and carcinomas of the stomach, the latter in an already advanced stages. In one female patient with carcinoma of the stomach the test was falsely positive. The negative test does not exclude a tumor, in a positive result should also be sought for a tumour in the upper gastrointestinal tract. Calculations of the valency of the test showed a good efficiency, sensitivity and specificity.