Test Details
Methodology
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
Result Turnaround Time
2 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Diazepam; nordiazepam (diazepam metabolite)
Use
Diazepam is effective in the management of generalized anxiety disorder and panic disorder in appropriately selected patients. Its use prior to endoscopy or cardioversion relieves anxiety and diminishes the patient's recall of the procedure. Preoperative use relieves anxiety and tension and may provide anterograde amnesia. Additional uses include the treatment of skeletal muscle spasms due to inflammation or trauma, spasticity (eg, multiple sclerosis, cerebral palsy, paraplegia, stiff-man syndrome), seizure disorders (eg, status epilepticus, febrile seizures), and alleviation of abstinence symptoms during alcohol withdrawal.
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Footnotes
References
Custom Additional Information
Diazepam is a muscle relaxant and antianxiety drug. Peak blood levels are achieved within an hour after oral dose. Half-life in adults is 21 to 37 hours. The major metabolite (nordiazepam) has a half-life in adults of 50 to 99 hours. It is the major metabolite also of clorazepate and prazepam. Minor active metabolites of diazepam are temazepam (3-hydroxydiazepam) and oxazepam (3-hydroxy-N-diazepam).1,2 Diazepam may exhibit synergism with barbiturates, tricyclic antidepressants, and amine oxidase inhibitors. Toxicity may be additive with other central nervous system depressants, and ethanol enhances the absorption of diazepam itself. Many cases of overdose are seen but few fatalities result from use of this drug alone. A frequent finding is a combination of this drug and ethanol.
Specimen Requirements
Specimen
Serum or plasma
Volume
1 mL
Minimum Volume
0.4 mL
Container
Red-top tube, lavender-top (EDTA) tube, or green-top (heparin) tube. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.
Collection Instructions
Transfer separated serum or plasma to a plastic transport tube. Oral: peak: one hour after dose; IV: peak: 15 minutes after dose.
Reference Range
Therapeutic: diazepam + nordiazepam: 0.2−2.5 μg/mL
Storage Instructions
Refrigerate.
Causes for Rejection
Gel-barrier tube
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 007989 | Diazepam (Valium), Serum | 49044-1 | 019976 | Diazepam, Serum | ug/mL | 3548-5 |
| 007989 | Diazepam (Valium), Serum | 49044-1 | 019984 | Nordiazepam, Serum | ug/mL | 3537-8 |
| 007989 | Diazepam (Valium), Serum | 49044-1 | 019985 | Total (Diaz+Nord) | ug/mL | 16757-7 |
| Order Code | 007989 | |||||
| Order Code Name | Diazepam (Valium), Serum | |||||
| Order Loinc | 49044-1 | |||||
| Result Code | 019976 | |||||
| Result Code Name | Diazepam, Serum | |||||
| UofM | ug/mL | |||||
| Result LOINC | 3548-5 | |||||
| Order Code | 007989 | |||||
| Order Code Name | Diazepam (Valium), Serum | |||||
| Order Loinc | 49044-1 | |||||
| Result Code | 019984 | |||||
| Result Code Name | Nordiazepam, Serum | |||||
| UofM | ug/mL | |||||
| Result LOINC | 3537-8 | |||||
| Order Code | 007989 | |||||
| Order Code Name | Diazepam (Valium), Serum | |||||
| Order Loinc | 49044-1 | |||||
| Result Code | 019985 | |||||
| Result Code Name | Total (Diaz+Nord) | |||||
| UofM | ug/mL | |||||
| Result LOINC | 16757-7 |