Test Code OXAZS Oxazepam, Serum
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (Serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Secondary ID
623016Useful For
Assessing compliance
Monitoring for appropriate therapeutic level
Assessing oxazepam toxicity
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Oxazepam, SSpecimen Type
Serum RedSpecimen Minimum Volume
0.3 mL
Specimen Stability Information
Specimen Type | Temperature | Time |
---|---|---|
Serum Red | Refrigerated (preferred) | 28 days |
Ambient | 28 days | |
Frozen | 28 days |
Reject Due To
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Clinical Information
Oxazepam is US Food and Drug Administration-approved for the management of anxiety disorders and is used to relieve anxiety, including that caused by alcohol withdrawal (symptoms may develop in people who stop drinking alcohol after drinking large amounts for an extended time). Oxazepam is in a class of medications called benzodiazepines. It works by slowing activity in the brain to allow for relaxation.
Oxazepam is metabolized by glucuronidation and has an intermediate half-life (approximately 4-16 hours) compared to other benzodiazepines. Common adverse effects include dizziness, headaches, somnolence and vertigo.
Reference Values
Therapeutic concentrations
Oxazepam: 200-1500 ng/mL
Cutoff concentrations by liquid chromatography tandem mass spectrometry:
Oxazepam: 10 ng/mL
Interpretation
Suggested therapeutic serum concentrations have been reported for oxazepam between 200 and 1500 ng/mL.
Cautions
No significant cautionary statements
Clinical Reference
1. Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 43
2. Hiemke C, Bergemann N, Clement HW, et al. Consensus guidelines for therapeutic drug monitoring in neuropsychopharmacology: Update 2017. Pharmacopsychiatry. 2018:51(1-02):9-62
3. Baselt RC. Disposition of Toxic Drugs and Chemical in Man. 12th ed. Biomedical Publications; 2020
Method Description
The internal standard mixture containing chlordiazepoxide-d5, diazepam-d5, nordiazepam-d5, oxazepam-d5, and temazepam-d5 is added to serum samples, mixed and centrifuged. The supernatant is diluted and injected on a liquid chromatography tandem mass spectrometer.(Unpublished Mayo method)
Day(s) Performed
Monday, Wednesday
Report Available
3 to 7 daysSpecimen Retention Time
14 daysPerforming Laboratory

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 |
---|---|---|
OXAZS | Oxazepam, S | 3886-9 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
623016 | Oxazepam | 3886-9 |