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Mayo Test ID CDP Chlordiazepoxide and Metabolite, Serum


Shipping Instructions


Ship specimen in amber vial to protect from light.



Specimen Required


Supplies: Amber Frosted Tube, 5 mL (T915)

Collection Container/Tube: Red top

Submission Container/Tube: Amber vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into amber vial within 2 hours of collection.


Useful For

Monitoring chlordiazepoxide therapy

 

Assessing toxicity

Method Name

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

Reporting Name

Chlordiazepoxide and metabolite, S

Specimen Type

Serum Red

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 14 days LIGHT PROTECTED
  Frozen  14 days LIGHT PROTECTED
  Ambient  24 hours LIGHT PROTECTED

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Clinical Information

Chlordiazepoxide (Librium) is a benzodiazepine widely used in the treatment of anxiety, alcohol withdrawal symptoms, and as a premedication for anesthesia. The mechanism of action of all benzodiazepines remains unclear. However, it is known that benzodiazepines facilitate gamma-amino butyric acid (GABA)-mediated neurotransmission in the brain. Benzodiazepines most likely facilitate the inhibitory presynaptic or postsynaptic reactions of GABA.

 

Chlordiazepoxide is metabolized to long-acting metabolites in the liver to the active metabolite nordiazepam (desmethyldiazepam), and the clearance of the drug is reduced considerably in the elderly and in patients with hepatic disease.

 

Therapeutic assessment should include measurement of both the parent drug (chlordiazepoxide) and the active metabolite (nordiazepam).

 

Since chlordiazepoxide has a wide therapeutic index and toxicity is dose-dependent, routine drug monitoring is not indicated in all patients

Reference Values

Therapeutic concentration:

Chlordiazepoxide: 400-3,000 ng/mL

Nordiazepam: 100-500 ng/mL

Interpretation

Chlordiazepoxide and nordiazepoxide combined concentrations above 5000 ng/mL have been associated with toxicity.

Cautions

The specimen must be protected from light.

Clinical Reference

1. Langman, LJ, Bechtel L, Meier BM, Holstege CP. Clinical toxicology. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:832-887

2. Burtis CA, Ashwood ER, Bruns DE, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. WB Saunders Company; 2011:1109-1188

3. Hiemke C, Baumann P, Bergemann N, et al. AGNP Consensus Guidelines for Therapeutic Drug Monitoring in Psychiatry: Update 2011. Pharmacopsychiatry. 2011;44(6):195-235

Method Description

The internal standard mixture containing chlordiazepoxide-d5, diazepam-d4, and nordiazepam-d5 is added to serum samples. The serum samples are treated with phosphate buffer and extracted via liquid/liquid extraction. The organic layer from the extraction is dried under nitrogen, reconstituted, and injected on a liquid chromatography tandem mass spectrometer.(Unpublished Mayo method)

Day(s) Performed

Monday, Wednesday

Report Available

2 to 7 days

Specimen Retention Time

14 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
CDP Chlordiazepoxide and metabolite, S 33060-5

 

Result ID Test Result Name Result LOINC Value
8610 Chlordiazepoxide 3457-9
37321 Nordiazepam 3537-8