ARUP's Laboratory Test Directory

Clozapine : 0098930

Mnemonic: CLOZAPINE

Methodology: Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Performed: Sun-Sat
Reported: 1-3 days
Specimen Required: Patient Prep: 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).

Stability (collection to initiation of testing): After separation from cells: Ambient: 5 weeks; Refrigerated: 2 months; Frozen: 2 months

Reference Interval:
Effective February 19, 2013
 
Therapeutic Range Not well established.
Toxic Level Greater than 2000 ng/mL

Interpretive Data: Clozapine concentrations between 100 and 700 ng/mL may correlate more with clinical response; however, non-responsiveness may occur within this range. For refractory schizophrenia, 350 ng/mL of clozapine is suggested to achieve a therapeutic response. After initial therapeutic response occurs, the dose should be progressively reduced to the minimum level necessary to maintain clinical remission. The likelihood of seizures and other side effects increase with clozapine levels greater than 1200 ng/mL and/or dosages greater than 600 mg/24h. Toxic concentrations may cause hypotension, cardiac abnormalities, respiratory depression, coma and death. A toxic range is not well established in children.
CPT Code(s): 80299
Cross References: Clozaril (Clozapine), FazaCol (Clozapine), Froidir (Clozapine), Leponex (Clozapine)