CPT Code(s):
- 83918
- 82570
Specimen Requirements:
Special instructions: Obtain samples as soon as possible after symptoms or presentation for highest diagnostic utility.
Type: Urine
Container: Urine cup or tube without additives
Sample volume: 3 mL
Minimum volume: 1 mL
Storage: Refrigerate or freeze as soon as possible to avoid artifacts related to bacterial metabolism.
Stability (collection to time of analysis):
- Ambient: 4 hours
- Refrigerated: 4 days
- Frozen: 4 weeks
Rejection criterion:
- Urine grossly contaminated with stool
Use:
This test is used to evaluate metabolic acidosis with increased anion gap, as well as to diagnose and monitor genetic and non-genetic disorders of amino acid and fatty acid metabolism and Kreb cycle.
Limitations
- Excretions of characteristic metabolites may not be elevated in some disorders when the patient is asymptomatic.
- Not all intermediates of amino acid and organic acid metabolism are identified with this test.
- Normal results on urine organic acid analysis does not exclude an inherited metabolic disorder as the etiology of the patient’s symptoms.
Methodology:
Liquid chromatography – tandem mass spectrometry (LC-MS/MS)
Reported:
Within 5 business days