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Test Code LAB418 Organic Acids, Qualitative, Urine

Performing Laboratory

St. Louis Children's Hospital Laboratory - Metabolic Genetics

Specimen Requirements

Patient Preparation: None

Container/Tube:

Preferred/Acceptable: Clean, plastic screw-cap urine collection container with no preservatives

Collection Volume: 6.0 (minimum 4.0 mL) urine

Submission Container/Tube: If sending specimen from an outside facility, place urine in a 10 mL screw-cap plastic transport vial and freeze. Place specimen to dry ice to keep frozen during transport.

Special Instructions: Send to lab promptly.

Sample Rejection

Specimens collected with preservative

Mislabled or unlabeled specimens

Logistics

Test Availability: Monday-Friday 

Cut-off time: Varies; batched once per day in a.m.

Turnaround Time: 3-5 days

Reference Values

Reference Interval: Interpretive report provided

Critical Value: None established

 

Methodology

Gas Chromatography/Mass Spectrometry (GC/MS)

Limitations

  • Patients on MCT (medium chain triglyceride) oil exhibit a pattern consistent with that seen in MCAD deficiency. Any patient showing significant peaks of adipate, sebacate, and suberate should be investigated for MCT oil.

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions:

  1. Mix specimen well and make two aliquot tubes.
  2. Aliquot one sample into a 10-mL plastic screw cap urine tube for Met. Gen. testing and freeze in MET. GEN. basket in freezer #1. 
  3. Aliquot a second sample for LUO urine creatinine testing. Give aliquot to the PRO bench and let them know they have a Met. Gen. specimen that needs to be frozen ASAP post analysis in freezer #1.
  4. Place the original collection container (with or without any remaining sample) in freezer #1.

NOTE: If specimen needs to be shared with UA bench, make sure they are aware that the specimen is shared, and original container needs to be placed in Met. Gen. basket in freezer #1.

 

Processed Volume: 6.0 mL (minimum 4.0 mL) urine

NO SPECIMEN SHOULD BE REJECTED FOR VOLUME. PLEASE CALL THE FLOOR TO NOTIFY THE NURSE THAT ADDITIONAL SPECIMEN IS NEEDED, SHOULD BE COLLECTED, AND SENT TO LAB TO ADD TO WHAT IS ALREADY COLLECTED. GIVE ALL SPECIMENS TO METABOLIC GENETICS TO DECIDE IF QNS.

Specimen Stability:

Specimen Type Temperature    Time              
urine (no preservative)     Ambient  1 hour
  Refrigerated      NA  
  Frozen   indefinetly    

Test Classification and CPT Code

83919

Test Classification: This test was developed and its performance characteristics determined by St. Louis Children's Hospital Clinical Laboratory. It has not been cleared or approved by the U.S. Food and Drug Administration.

LOINC

49287-6

Last Reviewed

08/2025