Sjoerdsma and his associates have described a simple qualitative urine test for the detection of increased amounts of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA).1 This test is based on the development of a purple color, specific for 5-hydrooxyindoles, on the addition of 1-nitroso-2-naphthol and nitrous acid. In normal individuals 5-hydroxyindoleacetic acid is excreted in the urine in amounts varying from 2 to 9 mg. per day, while in six patients with metastatic carcinoid (argentaffinoma) its excretion was found to vary from 76 to 580 mg. per day.2 These authors have not encountered other clinical conditions associated with an elevated excretion of 5-hydroxyindoleacetic acid and feel that the test is specific for metastatic carcinoid.
Due to the widespread interest in the action and metabolism of serotonin, it was felt that it would be interesting to perform this test on a large number of patients in an effort to determine
Mohler DN. EVALUATION OF THE URINE TEST FOR SEROTONIN METABOLITES. JAMA. 1957;163(13):1138. doi:10.1001/jama.1957.82970480004008a