Optimize drug therapy and monitor patient adherence.
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Timing of specimen collection: Pre-dose (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)
Whole blood. Gel separator tubes, light blue (citrate), or yellow (SPS or ACD solution).
After separation from cells: Ambient: 5 weeks; Refrigerated: 2 months; Frozen: 2 months
|Therapeutic Range||Not well established|
|Toxic Level||Total Clozapine and Metabolites: Greater than or equal to 1500 ng/mL|
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: Adverse effects to clozapine therapy may include tachycardia, drowsiness, hypotension, and seizures.
Therapeutic and toxic ranges are not well established in children.
This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.
Laboratory Developed Test (LDT)
|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|