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Test Code DIAZ G Diazepam and Nordiazepam, Serum

Reporting Name

Diazepam and Nordiazepam, S

Useful For

Assessing compliance


Monitoring for appropriate therapeutic level


Assessing toxicity

Specimen Required

Container/Tube: Red top

Specimen Volume: 0.5 mL

Specimen Type

Serum Red

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

Day(s) and Time(s) Performed


Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

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 0.1M phosphate buffer and extracted via liquid/liquid extraction with 50/50 (hexane/ethyl acetate). The organic layer from the extraction is dried under nitrogen, reconstituted in 95/5 (H2O/Methanol) and injected on a liquid chromatography-tandem mass spectrometer (LC-MS/MS).(Unpublished Mayo method)

Reference Values

Therapeutic concentrations

Diazepam and Nordiazepam: 200-2,500 ng/mL

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


G0480 (if appropriate)

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

Reject Due To


Mild OK; Gross OK


Mild OK; Gross OK


Mild OK; Gross OK


Serum gel tube


If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen (