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HelpEPIC ORDER CODE LAB468 Diazepam and Nordiazepam, Serum
Additional Codes
SQ: DIAZPM
Test Down Notes
This test is temporarily unavailable due to instrumentation issues. As an alternate, order ZW86 (1501SP). For additional details, see test update here.
Reporting Name
Diazepam and Nordiazepam, SUseful For
Assessing compliance
Monitoring for appropriate therapeutic level
Assessing diazepam toxicity
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedSpecimen Required
Collection Container/Tube: Red top (Serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial.
Specimen Minimum Volume
0.3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days | |
| Ambient | 14 days | ||
| Frozen | 14 days |
Reference Values
Therapeutic concentrations
Diazepam and Nordiazepam: 200-2,500 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 |
|---|---|---|
| DIA | Diazepam and Nordiazepam, S | 49044-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8629 | Diazepam | 3548-5 |
| 2475 | Nordiazepam | 3537-8 |
| 2459 | Diazepam and Nordiazepam | 16757-7 |
Clinical Information
Diazepam, a benzodiazepine derivative, is an anxiolytic agent that reduces neuronal depolarization resulting in decreased action potentials. It enhances the action of gamma-aminobutyric acid (GABA) by tightly binding to A-type GABA receptors, thus opening the membrane channels, and allowing the entry of chloride ions. It is also used as a muscle relaxant, procedural sedation agent, and sedative-hypnotic agent to treat withdrawal states (ie, ethanol), along with other conditions (seizures).
Diazepam is metabolized to several metabolites in the liver, including temazepam, oxazepam, and nordiazepam (desmethyldiazepam), and the clearance of the drug is reduced considerably in older individuals and in patients with hepatic disease.
Therapeutic assessment typically includes measurement of both the parent drug (diazepam) and the active metabolite (nordiazepam).
Interpretation
For seizures:
Serum concentrations are not usually monitored during early therapy because response to the drug can be monitored clinically as seizure control. If seizures resume despite adequate therapy, another anticonvulsant must be considered.
Toxicity is commonly seen when diazepam plus nordiazepam concentrations exceed 3000 ng/mL. Adverse effects of benzodiazepines in therapeutic doses usually reflect the drug's pharmacology and include sedation, slurred speech, and ataxia. Respiratory depression/arrest may occur with large overdoses or following rapid intravenous injection with short-acting benzodiazepines.
Clinical Reference
1. Langman LJ, Bechtel LK, Meier BM, Holstege C. 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:Table 60.2
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
3 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)