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HelpTest Code CDP Chlordiazepoxide and Metabolite, Serum
Test Down Notes
Effective December 14, 2023: This test is temporarily unavailable due to analytic issues. The downtime is expected to be >30 days. Order ZW86, (1080SP) as an alternate. See test notification here.
Reporting Name
Chlordiazepoxide and metabolite, SUseful For
Monitoring chlordiazepoxide therapy
Assessing toxicity
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedShipping 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.
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 |
Reference Values
Therapeutic concentration:
Chlordiazepoxide: 400-3,000 ng/mL
Nordiazepam: 100-500 ng/mL
Day(s) Performed
Monday, Wednesday
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 |
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
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)
Report Available
2 to 7 daysSpecimen Retention Time
14 daysReject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Neurology Specialty Testing Client Test Request (T732)
-Therapeutics Test Request (T831)