Organic Acids, Urine

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


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.


  1. Excretions of characteristic metabolites may not be elevated in some disorders when the patient is asymptomatic.
  2. Not all intermediates of amino acid and organic acid metabolism are identified with this test.
  3. Normal results on urine organic acid analysis does not exclude an inherited metabolic disorder as the etiology of the patient’s symptoms.


Liquid chromatography – tandem mass spectrometry (LC-MS/MS)


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