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Test Code CZPS Clonazepam and 7-Aminoclonazepam, Serum

Test Down Notes

This test is temporarily unavailable due to instrumentation issues. As an alternate, order FCLMS. For additional details, see test update here.

Useful For

Assessing patient compliance

 

Monitoring for appropriate therapeutic level

 

Assessing clonazepam toxicity

Method Name

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

Reporting Name

Clonazepam and 7-Aminoclonazepam, S

Specimen Type

Serum Red


Specimen Required


Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1.2 mL

Collection Instructions:

1. Draw blood immediately before next scheduled dose (minimum 12 hours after last dose).

2. Within 2 hours of collection, the specimen must be centrifuged and the serum aliquoted into a plastic vial.


Specimen Minimum Volume

0.6 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 14 days
  Frozen  28 days
  Ambient  72 hours

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus Reject

Clinical Information

Clonazepam (5 [2-chlorophenyl]-2, 3-dihydro-7-nitro-1, 4-benzodiazepin-2-one), a benzodiazepine is useful alone or as an adjunct in the treatment of certain seizures. In addition, it may be useful in patients with panic disorder and restless legs syndrome.

 

Clonazepam has no definite antiseizure and antipanic mechanism of action, although it is believed to be related to its capacity to enhance gamma-aminobutyric acid (GABA) activity, which is the major inhibitory neurotransmitter in the central nervous system. It is able to suppress the spike and wave discharges in absence seizures and decreases the frequency, duration, amplitude, and spread of discharge in minor motor seizures.

 

Clonazepam is highly protein bound (approximately 85%). It is extensively metabolized by hepatic cytochrome P450, family 3, subfamily A (CYP3A) to inactive metabolites and has a half-life of 30 to 40 hours.

Reference Values

Clonazepam

Anticonvulsant: 20-70 ng/mL

Anxiolytic: 4-80 ng/mL

Some individuals may show therapeutic response outside of these ranges or may display toxicity within the therapeutic range, thus interpretation should include clinical evaluation. 

Note: Therapeutic ranges are for specimens collected at trough (ie, immediately before next scheduled dose). Levels may be elevated in non-trough specimens.

Interpretation

The therapeutic range varies depending on the indication.

 

Some individuals may respond well outside of these ranges or may display toxicity within the therapeutic range, and thus, interpretation should include clinical evaluation.

 

The possibility of toxicity is increased when levels exceed 100 ng/mL.

Cautions

Specimens that are obtained from gel tubes must be removed from the gel within 2 hours.

Day(s) Performed

Monday, Wednesday

Report Available

3 to 7 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80299

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CZPS Clonazepam and 7-Aminoclonazepam, S 104541-8

 

Result ID Test Result Name Result LOINC Value
65044 Clonazepam 3494-2
41782 7-Aminoclonazepam 28059-4

Forms

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