Home
HelpTest Code LAB7543 Diazepam and Nordiazepam, Serum
Additional Codes
DIA
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.
Useful 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
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.
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extraction is dried under nitrogen, reconstituted, and injected on a liquid chromatography tandem mass spectrometer.(Unpublished Mayo method)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)