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Test Code
This test is a lab developed test. For further information, see the Compliance Remarks section below.
SynonymsClozaril; Fazaclo
Container TypeRed top tube (plain)
Supply Item Number1372
Specimen TypeSerum
Preferred Volume0.25 mL
Emergency Minimum Volume0.1 mL
Patient PrepTiming of specimen collection: Pre-dose (trough) draw - At steady state concentration.
Specimen ProcessingSeparate serum from cells and transfer to a standard PAML aliquot tube.
Store and TransportRefrigerated
StabilityRoom Temp 2 weeks  Refrigerated 2 weeks  Frozen (-20 °C) 1 month  
Unacceptable ConditionDO NOT use gel separator tubes (Corvac®, SST or equivalent) for the collection of blood samples for this test.
Alternate SpecimensEDTA, sodium heparinized or sodium fluoride/potassium oxalate plasma (lavender, green or grey top tube)
Reference LaboratoryPAML
CPT Codes80159, (HCPCS G0480)
Interface Order Code80299.Z69
Billing CodeCLONOR
Test ScheduleMon, Wed, Fri
Turnaround Time1-3 days
MethodTandem Mass Spectrometry
Reference Ranges
NorclozapineNot Establishedng/mL
Patients dosed with 400 mg clozapine daily for 4 weeks were most liekly to exhibit a therapeutic effect whe nteh sum of clozapine and norclozapine concentrations were at least 450 ng/ml.
Compliance RemarksThis test was developed and its performance characteristics determined by PAML. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. PAML is authorized under Clinical Laboratory Improvement Amendments (CLIA) to perform high-complexity testing.
NotesClozapine is associated with severe neutropenia (absolute neutrophil count (ANC) less than 500/uL). The requirements to prescribe, dispense, and receive clozapine are incorporated into a single, shared program called the Clozapine Risk Evaluation and Mitigation Strategy (REMS). A REMS is a strategy to manage known or potential risks associated with a drug or group of drugs, and is required by the FDA for clozapine to ensure that the benefits of the drug outweigh the risk of severe neutropenia. The Clozapine REMS Program replaces the individual clozapine patient registries and the National Non-Rechallenge Master File (NNRMF). For additional information about the Clozapine REMS Program, please call 844-267-8678.

Interface Codes
typeorder codetest descriptionresult coderesult descriptionunitsdecimal placesloinc code
r80299.Z69Clozapine/Norclozapine80299.Z62Clozapineng/mL 6896-5
r80299.Z69Clozapine/Norclozapine80299.Z68Norclozapineng/mL 10992-6