Published on April 03, 2025

Clozapine Level, Serum

Tube Type = Gold Top

No Gel in Red Top Bullet

Tube type

Test ID LAB17033
EPIC ORDER CLOZAPINE LEVEL, SERUM
CPT Code(s) 80159
Group/Individual Test Individual 
Laboratory Core Laboratory
Tube Station STAT: 888; Routine: 30
Specimen Routine: 2 mL blood/navy blue plain tube or red plain tube; See Comments
Micro: 0.75 mL blood/red bullet
Availability Routine: 24/7
Turnaround Time STAT: 1 hour; Routine: 2 hours
Reference Range Therapeutic: 350-600 ng/mL
Comments
  • Whole Blood sample must be spun and aliquoted within 2 hours of collection
  • Red top tubes must NOT contain Serum Separator Gel
  • Collection information: Trough levels collected 12 hours after the last dose at steady state (3 days after a dose change) are recommended for clozapine levels. 
  • This test provides a total clozapine level. If metabolite levels are needed, do not order this test. Order LAB5611 (Clozapine and metabolites). 

Reviewed by J. Carr on January 05, 2026

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514