Dextro/Levo Methorphan, Serum/Plasma

Test Code

37448

CPT Codes
80299

Preferred Specimen

1 mL serum collected in a red-top tube (no gel)

Minimum Volume

0.3 mL

Other Acceptable Specimens

Plasma collected in: EDTA (lavender-top) or EDTA (pink-top) tube

Instructions

Promptly centrifuge and separate serum or plasma into a plastic screw capped vial using approved guidelines.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 7 days
Refrigerated: 29 days
Frozen: 24 months

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Polymer gel separation tube (SST or PST)

Methodology
Gas Chromatography (GC)

FDA Status
This test was developed and its performance characteristics determined by NMS Labs. It has not been cleared or approved by the US Food and Drug Administration.

Setup Schedule

Set up: As needed; Report available: 4 days

Report Available

4 Days

Reference Range

Mean peak serum concentration following a single 20 mg oral dose of Dextromethorphan: approximately 2 ng/mL.
Peak plasma levels on the 7th day of a 30 mg q.i.d. regimen of
Dextromethorphan: 2.4 ng/mL (range 0.5-5.9) in 14 extensive metabolizers;
207 ng/mL (range 182-231 in 2 poor metabolizers

This test is not chiral specific; therefore, Dextromethorphan and/or Levomethorphan may be present

Clinical Significance

Therapeutic drug monitoring.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.