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Clozapine and Metabolites, Serum or Plasma, Quantitative
2013433
Ordering Recommendation

Optimize drug therapy and monitor patient adherence.

Mnemonic
CLOZAP SP
Methodology
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Performed
Sun-Sat
Reported
1-3 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Timing of specimen collection: Pre-dose (trough) draw - At steady state concentration. 
Collect
Plain red. Also acceptable: Lavender (K2 or K3EDTA) or pink (K2EDTA). 
Specimen Preparation
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) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
Whole blood. Gel separator tubes, light blue (citrate), or yellow (SPS or ACD solution). 
Remarks
 
Stability
After separation from cells: Ambient: 5 weeks; Refrigerated: 2 months; Frozen: 2 months 
Reference Interval
Therapeutic RangeNot well established
Toxic LevelTotal 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, non-responsiveness may also occur within this range. For refractory schizophrenia, clozapine concentrations greater than 350 ng/mL are suggested to achieve a therapeutic response.

Toxicity: Toxic ranges are not well established. Serum/plasma concentrations greater than or equal to 1500 ng/mL (clozapine, norclozapine and clozapine-N-oxide combined) may cause drug-induced agranulocytosis, Stevens-Johnson syndrome, seizures, hypotension, cardiovascular abnormalities, drowsiness, and death.

Therapeutic and toxic ranges are not well established in children.

Compliance Statement B: This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Note
CPT Code(s)
80159
Components
Component Test Code*Component Chart NameLOINC
2013458Clozapine, S/P, Quant6896-5
2013459Norclozapine, S/P, Quant10992-6
2013460Clozapine-N-Oxide, S/P, Quant
2013461Total Clozapine and Metabolites
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Clopine
  • Clozaril
  • Denzapine
  • FazaClo
  • Versacloz
  • Zaponex