Test Overview
Test Methodology

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

Test Usage

Therapeutic Drug Monitoring

Reference Range *

Clozapine: >350 ng/mL; Clozapine & Norclozapine: >450 ng/mL.

Test Details
Days Set Up
Monday - Friday
Analytic Time

3 - 5 days

Soft Order Code
CLOZ
MiChart Code
Clozapine (Clozaril), Level
Synonyms
  • Clozaril
  • CLOZ
  • Clozapine, Plasma/Serum
Laboratory
Sendout
Reference Laboratory
Mayo CLZ (61657)
Section
Special Testing
Specimen Requirements
Collection Instructions

Collect specimen in a red top tube; do not use SST tube. Centrifuge, aliquot serum into a plastic container and refrigerate.

Rejection Criteria
SST tube not acceptable.
Yellow Top Tube
Red Top Tube
Normal Volume
1.0 mL serum
Minimum Volume
0.6 mL serum
Additional Information

Clozapine is an antipsychotic agent. Peak clozapine concentrations are reached in 1-6 hours following oral dosage. Elimination half-life is 4-16 hours once steady state levels have been reached. Norclozapine has minimal therapeutic activity. Test sent to Mayo Medical Laboratories; performed by Mayo New England.

Billing
CPT Code
80159
Fee Code
32105
LOINC
6896-5
NY State Approved
No