title: The clinical and laboratory correlates of an increased urinary 5-hydroxyindoleacetic acid.
abstract: Over a five-and-a-half-year period, there were 298 laboratory requests for urinary 5-hydroxyindoleacetic acid (5-HIAA). The clinical and laboratory associations of the 24 patients in which there were 43 urinary 5-HIAA 24-h collection results greater than the laboratory upper reference limit are detailed. Four were confirmed carcinoid tumours and two were phaeochromocytomas. Flushing was a prominent symptom in 46% and diarrhoea or altered bowel habit in 37%. Associated with the raised urinary 5-HIAA values were increased levels of 4-hydroxy-3-methoxymandelic acid and homovanillic acid in 14.3% and 21%, respectively, of those collections where the metabolites were requested. Diagnostic imaging was performed in 57%. While the specificity was 88%, 5-HIAA is relatively insensitive in the diagnosis of carcinoid tumours and a more widespread use of diagnostic imaging including isotope scanning with labelled metaiodo-benzylguanidine, vasoactive intestinal peptide and octreotide is suggested.
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000652:urine*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002276:Carcinoid Tumor / Q000150:complications / Q000175:diagnosis / Q000652:urine*; D003952:Diagnostic Imaging; D003967:Diarrhea / Q000209:etiology / Q000652:urine; D005260:Female; D005483:Flushing / Q000209:etiology / Q000652:urine; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine*; D007494:Ireland; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000652:urine*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D006897:Hydroxyindoleacetic Acid