Urine organic acids

Clinical Utility:

This gas chromatography mass spectrometry (GCMS) qualitative test is diagnostic for a large number of organic acidemias. Disorders Identified by GCMS. It is also used for confirmation of some disorders diagnosed by MS/MS blood spot.

Specimen Types:

The most appropriate sample material is a random urine sample (2-5 ml; minimum 0.5 ml) in a tube and shipped frozen with dry ice, no preservatives. Frozen urine with coolant pack is acceptable from local hospitals. Lyophilized (freeze-dried) urine in a plastic tube is acceptable. Dry urine spots on Guthrie cards are also acceptable.

Turn-around Time:

Routine: 3-7 days from receipt of sample

Stat: 24 hours from receipt of sample

Test Limitations & Interfering Substances:

This test sometimes yield false negative results if the patient is in a compensated metabolic condition, and therefore repeat analysis on another sample might be required. No interfering substances are known. The test as carried out in our lab detects sugars and occasionally is useful in diagnosing galactosemia, but is not a definitive method.