Clozapine and Metabolites, Serum or Plasma, Quantitative
Ordering Recommendation
Optimize drug therapy and monitor patient adherence.
New York DOH Approval Status
Specimen Required
Timing of specimen collection: Predose(trough) draw - at steady -state concentration.
Plain red. Also acceptable: Lavender (K2 or K3EDTA) or pink (K2EDTA).
Separate serum or plasma from cells within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP standard transport tube.(Min: 0.5 mL)
Refrigerated.
Whole blood. Gel separator tubes, light blue (citrate), or yellow (SPS or ACD solution).
After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 3 months
Methodology
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Performed
Sun-Sat
Reported
1-5 days
Reference Interval
Therapeutic Range | Not well established |
Toxic Level | Total Clozapine and Metabolites: Greater than or equal to 1500 ng/mL |
Interpretive Data
Therapeutic ranges are not well established. Clozapine is metabolized to norclozapine and clozapine-N-oxide. Clozapine concentrations between 100 and 700 ng/mL may correlate more with clinical response; however, nonresponsiveness may also occur within this range. For refractory schizophrenia, clozapine concentrations greater than 350 ng/mL are suggested to achieve a therapeutic response.
Toxicity: Adverse effects to clozapine therapy may include tachycardia, drowsiness, hypotension, and seizures.
Therapeutic and toxic ranges are not well established in children.
Laboratory Developed Test (LDT)
Note
Hotline History
Hotline History
CPT Codes
80159
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
2013458 | Clozapine, S/P, Quant | 6896-5 |
2013459 | Norclozapine, S/P, Quant | 10992-6 |
2013460 | Clozapine-N-Oxide, S/P, Quant | 85497-6 |
2013461 | Total Clozapine and Metabolites | 12375-2 |
Aliases
- Clopine
- Clozaril
- Denzapine
- FazaClo
- Versacloz
- Zaponex