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Beaumont Laboratory

Clonazepam Level

Klonopin, Clonopin, Antrim #16980, EPIC: LAB5383, SOFT: CLONZ

Specimen Collection Criteria

Collect: One plain Red-top tube. (Minimum Whole Blood: 2.0 mL)

See Minimum Pediatric Specimen Requirements for Microtainer® collection.
Do not use Serum Separator Tubes.
Time of Collection:
Trough, just prior to the next dose.
Record the exact time of specimen collection on the tube or in the computer system.

Physician Office/Drawsite Specimen Preparation

Let specimens clot 30-60 minutes. Centrifuge specimen to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection. (Min: 0.5 mL serum)

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8°C or 36-46°F). (Min: 0.5 mL serum)

Rejection Criteria

  • Serum Separator (SST) tubes.
  • Severely lipemic or hemolyzed specimens. 


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 8 hours
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Frozen (-20°C/-4°F or below): 2 months


Royal Oak Toxicology Laboratory.


Monday, Thursday.
Results available the same day as testing performed (1-4 days).

Reference Range

Therapeutic Range: 15-75 ng/mL.
Critical Range: Greater than 100 ng/mL.

Test Methodology

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

This test was developed and its performance characteristics determined by Beaumont Health. It has not been cleared or approved by the FDA. The Laboratory is regulated under CLIA as qualified to perform high-complexity testing. This test is used for clinical purposes and should not be regarded as investigational or for research.


The primary value of Clonazepam monitoring may be in insuring that patients achieve sufficient serum levels to assure an adequate clinical trial. It may also be valuable in evaluating symptoms of CNS toxicity.

Clinical Utility

This assay is used to monitor the therapeutic drug level and evaluate the toxicity of clonazepam. Clonazepam is a long-acting benzodiazepine. It is used in epilepsy both in prophylaxis when other agents have failed and in status epilepticus utilizing intravenous administration. It is increasingly used in psychiatry as a treatment for panic disorder.

CPT Code

80346 (alternate: G0480).

Test Codes

Antrim #16980, EPIC: LAB5383, SOFT: CLONZ

Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.