title: 'Sweet Dreams', 'Happy Days' and elevated 24-h urine 5-hydroxyindoleacetic acid excretion.
abstract: We report two patients with markedly elevated 24-h urine 5-hydroxyindoleacetic acid (5-HIAA) excretion due to over-the-counter (OTC) self-medication with 5-hydroxytryptophan (5-HTP). It is important to recognize that OTC medication may cause increased 'false-positive' 5-HIAA excretion to prevent undue patient anxiety and unnecessary further investigation for carcinoid disease. Discordance between chromogranin A and 24-h urine 5-HIAA results should alert to the possibility of false-positive or -negative laboratory results.
authors.affiliation: Department of Clinical Chemistry, New Cross Hospital, Wolverhampton, West Midlands WV10 0QP. magnus.hallin@nhs.net
authors.forename: Magnus Lars Peter
authors.initials: ML
authors.lastname: Hallin
authors.forename: Kamala
authors.initials: K
authors.lastname: Mahmoud
authors.forename: Ananth
authors.initials: A
authors.lastname: Viswanath
authors.forename: Rousseau
authors.initials: R
authors.lastname: Gama
mesh_terms: D006916:5-Hydroxytryptophan / Q000008:administration & dosage / Q000378:metabolism*; D000368:Aged; D002851:Chromatography, High Pressure Liquid; D053379:Chromogranin A / Q000097:blood; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine*; D008303:Malignant Carcinoid Syndrome / Q000175:diagnosis / Q000652:urine; D008875:Middle Aged; D004366:Nonprescription Drugs / Q000008:administration & dosage / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism
chemical_list: D053379:Chromogranin A; D004366:Nonprescription Drugs; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006916:5-Hydroxytryptophan