Test Code DIA Diazepam and Nordiazepam, Serum
Additional Codes
CNE Order Code: Diazepam
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 (1501SP) as an alternate. See test notification here.
Reporting Name
Diazepam and Nordiazepam, SUseful For
Assessing compliance
Monitoring for appropriate therapeutic level
Assessing diazepam toxicity
Performing Laboratory

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 |
---|---|---|
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
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 |
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.
Report Available
3 to 7 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 a Therapeutics Test Request (T831) with the specimen.