Amino Acids, Urea Cycle Disorders Panel, Plasma
Use
This test is useful for the follow-up of patients with urea cycle disorders. Urea cycle disorders are a group of inherited disorders of nitrogen detoxification resulting from defects in any of the enzymes involved in the urea cycle. Disruption of the urea cycle can lead to the accumulation of ammonia, which is toxic to the nervous system. Plasma amino acid analysis can aid in diagnosing a urea cycle disorder and for follow-up of a known patient.
Special Instructions
Patient preparation requires fasting for 4 hours; infants should have specimens collected before the next feeding, ideally after 2-3 hours without total parenteral nutrition. Forms such as the Biochemical Genetics Test Request may be needed if not ordering electronically.
Limitations
This test should not be performed on body fluids other than plasma. It is specifically designed to measure amino acids related to urea cycle disorders, and should not be used as a general screen for other metabolic conditions. Specimens with gross hemolysis, lipemia, or icterus are acceptable for testing. Reference values are for fasting patients only.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 100368-0
- 20643-3
- 20640-9
- 32227-1
- 20637-5
- 20652-4
- 49247-0
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.5 mL
Minimum Volume
0.3 mL
Container
Green top (sodium heparin)
Collection Instructions
Collect specimen and place on wet ice. Centrifuge immediately or within 4 hours if refrigerated. Ensure no buffy coat is transferred, aliquot plasma into a plastic vial, and freeze.
Patient Preparation
Fasting: 4 hours, required; infants should have specimen collected before next feeding.
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |