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Clozapine Level

Clozaril

Test Codes

Antrim #17062, EPIC: LAB5384, SOFT: CLOZA

Department

Toxicology

Specimen Collection Criteria

Collect: One plain Red-top tube. (Minimum Whole Blood: 2.0 mL)

Do not use Serum Separator Tubes.
Time of Collection: Trough, just prior to the next dose.
Record the exact time of specimen collection on the tube or in the computer system.

Physician Office/Draw Specimen Preparation

Let specimens clot 30-60 minutes. Refrigerate (2-8°C or 36-46°F) the collection tube within two hours of collection. (Minimum: 2.0 mL blood)

Preparation for Courier Transport

Transport: Collection tube, refrigerated (2-8°C or 36-46°F). (Minimum: 3.0 mL blood)

Rejection Criteria

• Serum Separator (SST) tubes.
• Severely lipemic or hemolyzed specimens.  

In-Lab Processing

Let specimens clot 30-60 minutes. Centrifuge specimen to separate serum from cells. Deliver an aliquot of serum or the collection tube immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Frozen (-20°C/-4°F or below): 2 months

Laboratory

Royal Oak Toxicology Laboratory

Performed

Tuesday, Wednesday, Friday.
Results available the same day as testing performed (1-4 days).

Reference Range

Therapeutic Range: 300-700 ng/mL.
Critical Value: Greater than 1000 ng/mL.

Test Methodology

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

This test was developed and its performance characteristics determined by Beaumont Health. It has not been cleared or approved by the FDA. The Laboratory is regulated under CLIA as qualified to perform high-complexity testing. This test is used for clinical purposes and should not be regarded as investigational or for research.

Interpretation

Clozapine is an antipsychotic medication associated with seizures and hematological toxicity at elevated serum concentrations. Caffeine, Fluvoxamine, Cimetidine, Sertraline have increased Clozapine steady-state concentrations via metabolic inhibition. Phenytoin, Phenobarbital, Carbamazepine and other metabolic inducing agents will decrease Clozapine steady-state concentrations.

Clinical Utility

Clozapine is indicated for the management of severely ill schizophrenic patients who fail to respond adequately to standard antipsychotic drug treatment. This assay is used for the therapeutic monitoring and toxicity assessment of clozapine.

CPT Codes

80159
LOINC: 6896-5, Last Dose Date  9742-4, Last Dose Time 29637-6

Contacts

Last Updated

1/20/2023