3-O-Methyldopa (Plasma)

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Turnaround Time: 10 - 14 Days
CPT Code:


Test Type: Plasma, frozen 1.0 Ml


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)


Collection Details:

Collection Instructions:

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.