Clozapine

Test Code

1769

CPT Codes
80159

Includes

Clozapine and Norclozapine

Preferred Specimen

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

Minimum Volume

1 mL

Other Acceptable Specimens

Plasma collected in an: EDTA (lavender-top), or sodium or lithium heparin (green-top) tube

Transport Container

Plastic screw-cap vial

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 24 hours
Refrigerated: 5 days
Frozen: 30 days

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

Gross hemolysis • Gel barrier/Serum Separator Tube (SST^®)

Methodology
Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Mon-Sat; Report available: 2 days

Reference Range

Norclozapine

25-400 mcg/L

Clozapine
The therapeutic response begins to appear at 100 mcg/L
Refractory schizophrenia appears to require a therapeutic concentration of at least 350 mcg/L (trough, at steady state).
Toxic range: >900 mcg/L

Clinical Significance

Clozapine is an atypical antipsychotic agent. Norclozapine has minimal therapeutic activity.

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.