Benzodiazserplscnc
A test that measures the amount of benzodiazepine drugs in your blood to monitor treatment or check for drug presence.
{"Measures benzodiazepine levels in serum or plasma","Helps doctors monitor medication effectiveness and safety","Used to check medication compliance or diagnose overdose","Sample is collected via blood draw","Results help guide dosing decisions"}
Key facts at a glance
- LOINC
- 32052-3
- Short code
- BENZSP
- Synonyms
- Benzodiaz SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube (no anticoagulant) or serum separator tube (SST, tiger-top); plasma collected in sodium fluoride/potassium oxalate (gray-top) tube for stability of certain analytes
- Units
- N/A
- Ref low
- 0
- Ref high
- 100
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (e.g., enzyme immunoassay, fluorescence polarization immunoassay, or chemiluminescent immunoassay); confirmation by LC-MS/MS or GC-MS
- CPT
- 80307
- SNOMED
- 33351009
- Specimen volume
- 1-2 mL serum or plasma; minimum 0.5 mL
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 30
- TAT
- 4–72 hours
- Order
- routine
What is this test?
The Benzodiazepine test measures the concentration of benzodiazepine drugs in your blood serum or plasma. Benzodiazepines are a class of prescription medications commonly used to treat anxiety, insomnia, seizures, and muscle spasms. Examples include diazepam (Valium), lorazepam (Ativan), alprazolam (Xanax), and clonazepam (Klonopin).
Why is this test performed?
This test may be ordered for several reasons: to monitor therapeutic drug levels in patients taking benzodiazepines, to ensure the drug is within the effective range, to check patient compliance with prescribed medications, to evaluate suspected overdose or toxicity, or to detect drug use in certain clinical situations.
How is the test done?
A healthcare professional will draw a blood sample from a vein in your arm. The sample is then sent to a laboratory for analysis. The test measures the amount of benzodiazepine present in your blood serum or plasma, and results are typically reported in nanograms per milliliter (ng/mL) or micrograms per liter (μg/L), though the specific unit may vary by laboratory.
How to prepare for the test?
Follow your doctor's instructions regarding medication timing. Inform your healthcare provider about all medications, supplements, and herbal products you are taking, as some substances may affect test results. Fasting is usually not required for this test, but follow any specific instructions provided by your healthcare team.
Understanding your results
Results are interpreted by your doctor based on the specific benzodiazepine being tested, your dosage, time since last dose, and your individual health condition. Therapeutic ranges vary by medication. Your doctor will explain whether your results are within the expected range, too high, or too low, and what this means for your treatment plan.
Reference range
Negative: <100 ng/mL (cutoff varies by laboratory and methodology). Therapeutic and toxic ranges depend on the specific benzodiazepine (e.g., diazepam, nordiazepam, oxazepam, temazepam, alprazolam, clonazepam, lorazepam, midazolam).N/A
No fasting required. Inform the ordering clinician of all current medications, including prescribed benzodiazepines, over-the-counter drugs, and herbal supplements, as many benzodiazepines share cross-reactive metabolites.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
How long does benzodiazepine stay in your blood?
Will this test show all types of benzodiazepines?
Do I need to stop my medication before the test?
What do low benzodiazepine levels mean?
What do high benzodiazepine levels mean?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 15, 2026. · Read our editorial policy