Tryptophan, Random, Urine

Casandra

Casandra Test Code MC53338Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID TRYPUCPT Code 82131

Tryptophan, Random, Urine

Clinical Use

Use

This test aids in the screening and monitoring of Hartnup disease by measuring urinary tryptophan, an essential amino acid, which is metabolically critical for synthesis of serotonin, melatonin, and niacin. Hartnup disease is an autosomal recessive disorder characterized by impaired neutral amino acid transport, leading to increased renal excretion of tryptophan and potential niacin deficiency, resulting clinically in pellagra-like rash and neurological symptoms such as ataxia. ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/Overview/83823?utm_source=openai))

Special Instructions

For ordering, the patient’s age is required along with clinical context including family history, diet, drug therapy, and clinical condition (e.g., asymptomatic or acute episode). A Biochemical Genetics Test Request form (T798) must be submitted if ordering is not electronic. ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/Overview/83823?utm_source=openai))

Limitations

Conventional amino acid profiling methods using ninhydrin or HPLC are limited by coelution with other compounds; this test uses LC‑MS/MS for interference‑free quantitation. Urine concentrations of tryptophan are not diagnostic in isolation and must be interpreted in the clinical context. ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/Overview/83823?utm_source=openai))

Test Details

New York Approved