USE OF LABELLED TRIOLEIN, VITAMIN A, AND D-XYLOSE IN THE DIAGNOSIS OF MALABSORPTION.

This paper discusses the type of results given by a group of test procedures used in the study of small intestinal dysfunction. While the chemical estimation of faecal fat remains the most valuable criterion for the laboratory detection of malabsorption, the occurrence of abnormal faecal or blood radioactivity also denotes the presence of malabsorption, although some patients with staetorrhoea appear to ;absorb' labelled triolein normally. Analysis of data from the other tests shows that steatorrhoea is not necessarily present in patients who give abnormal results and that the presence of malabsorption does not preclude a normal capacity for handling the test substances. These reservations impair the value of the vitamin A and xylose ;tolerance' tests and serum carotene levels as screening procedures for the determination of malabsorption states. On the other hand, these tests show patterns of results which are useful in differentiating idiopathic from secondary steatorrhoea, since patients with secondary malabsorption often handle one or more of these test substances normally.