Find Locations
For hours, walk-ins and appointments.Expected Turnaround Time
10 - 14 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Specimen Requirements
Specimen
Plasma, frozen
Volume
1.0 mL
Minimum Volume
0.5 mL
Container
Lavender-top (EDTA) tube, green-top (sodium heparin) tube
Collection
Collect 2-4 mL blood in sodium heparin (green-top) or EDTA (purple-top) tube.
Storage Instructions
Remove plasma and freeze at -20°C. Store frozen at -20°C and ship frozen.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | Unstable |
Refrigerated | Unstable |
Frozen | Indefinitely |
Causes for Rejection
Thawed sample
Test Details
Use
Aromatic L-amino acid decarboxylase (AADC) is a pyridoxal 5'-phosphate dependent enzyme responsible for the formation of dopamine and serotonin. AADC deficiency is a congenital autosomal recessive metabolic disorder that causes hypotonia, hypokinesia, oculogyric crises, and signs of autonomic dysfunction beginning in infancy. In AADC deficiency, L-dopa accumulates and can be methylated by catechol O-methyltransferase using S-adenosylmethionine as the methyl donor to form 3-O-methyldopa (3-OMD). 3-OMD is more stable than L-dopa and can be detected in blood.
Limitations
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 620176 | 3-O-Methyldopa Plasma | 50141-1 | 620177 | Result | 50141-1 | |
| 620176 | 3-O-Methyldopa Plasma | 50141-1 | 620178 | Interpretation | N/A | |
| 620176 | 3-O-Methyldopa Plasma | 50141-1 | 630857 | 80563-0 |
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