Clozapine, Serum or Plasma
Use
Clozapine is used primarily to evaluate toxicity and monitor therapeutic levels in patients. It is essential for correlating the efficacy of the drug with plasma concentration, particularly as the drug is absorbed rapidly with peak plasma concentrations occurring within 30 minutes to six hours. Therapeutic drug monitoring is crucial due to the variable metabolism of clozapine, which can be influenced by pharmacogenomics and coadministration of other agents that affect CYP1A2 and CYP3A4 activity, potentially leading to significant changes in drug levels.
Special Instructions
Not provided.
Limitations
The test has not been cleared or approved by the Food and Drug Administration. Pharmacogenomics and coadministration of other agents can complicate the dose and plasma concentration correlation. Cytochrome P450 oxidases, especially CYP1A2 and CYP3A4, can significantly influence clozapine levels. Enzyme inducers, like carbamazepine, can lead to decreased clozapine concentration, while inhibitors like amiodarone, fluvoxamine, and others may increase levels.
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 65632-2 - cloZAPine+Nor pnl SerPl
- 6896-5 - cloZAPine SerPl-mCnc
- 10992-6 - Norclozapine SerPl-mCnc
- 12375-2 - cloZAPine+Nor SerPl-mCnc
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.3 mL
Container
Red-top tube, lavender-top (EDTA) tube, or green-top (heparin) tube. Do not use a gel-barrier tube.
Collection Instructions
Transfer separated serum or plasma to a plastic transport tube.
Storage Instructions
Room temperature
Causes for Rejection
Gel-barrier tube
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
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