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Test Code LAB7499 Clozapine, Serum

Additional Codes

CLZ

Secondary ID

42366

Useful For

Monitoring patient compliance of clozapine treatment

 

An aid to achieving desired serum levels

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Specimen Type

Serum Red


Ordering Guidance


 



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Red top (serum gel/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:  

1. Collect specimen immediately before next scheduled dose.

2. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.

Additional Information: Therapeutic range (trough level) applies to specimens collected immediately prior to next dose.


Specimen Minimum Volume

0.6 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  7 days
Medical University of South Carolina Note:

On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318.  Send in plastic vial, Refrigerated.
 
Off-campus collections: 
Centrifuge and aliquot within 2 hours.

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Reference Values

Clozapine

Therapeutic range: 350-600 ng/mL

 

Norclozapine

Therapeutic range: Not well established

 

Clozapine + Norclozapine

Therapeutic range: Not well established

Interpretation

The effectiveness of clozapine treatment should be based on clinical response and treatment should be discontinued in patients failing to show an acceptable clinical response.

Method Description

Deuterated stable isotope of clozapine is added to the serum sample as an internal standard. Protein is precipitated from the mixture by the addition of acetonitrile. Clozapine, norclozapine, and the internal standard are extracted from the resulting supernatant by an online extraction utilizing high-throughput liquid chromatography. This is followed by conventional liquid chromatography and analysis on a tandem mass spectrometer equipped with a heated nebulizer ion source.(Unpublished Mayo method)

Day(s) Performed

Monday through Friday

Report Available

3 to 5 days

Specimen Retention Time

2 weeks

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

80159

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CLZ Clozapine, S 65632-2

 

Result ID Test Result Name Result LOINC Value
33840 Clozapine 6896-5
33841 Norclozapine 10992-6
33842 Clozapine+Norclozapine Total 12375-2

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.