Urinary serotonin in the diagnosis of carcinoid tumors
Feldman, J.M.
Clinical Chemistry 32(5): 840-844
1986
ISSN/ISBN: 0009-9147 PMID: 2421946 Document Number: 280676
To determine whether measurement of serotonin in urine would give useful complementary information to the usual measurement of 5-hydroxyindoleacetic acid (5-HIAA) in urine and platelet serotonin in platelets, I measured these analytes in 75 consecutive patients with carcinoid tumors, and found that 75% had above-normal urinary 5-HIAA excretion, 64% had above-normal serotonin excretion, and 64% had above-normal platelet serotonin concentration. Six patients had increased urinary serotonin, but 5-HIAA excretion and platelet serotonin concentration were normal. Only two of a further 50 patients with solid noncarcinoid tumors.sbd.and none of 55 patients with flushing or diarrhea, who did not prove to have a carcinoid tumor.sbd.had increased urinary serotonin. Ingestion of four bananas (a food rich in serotonin) increased urinary 5-HIAA but not urinary serotonin excretion of seven normal subjects. Evidently, measurement of urinary serotonin excretion is helpful in the evaluation of patients with suspected carcinoid tumors.