Laboratory Test Overview: What This Test Is, Why It Is Done, and What to Expect
This test measures the amount of barbiturate drugs in your blood to ensure proper dosing and safety.
{"Barbiturate drugs are CNS depressants used for sedation, anesthesia, or seizure control","The test helps doctors monitor drug levels and prevent toxicity","Blood samples are typically collected before taking the morning dose"}
Key facts at a glance
- LOINC
- 4136-8
- Short code
- BARBDOSE
- Synonyms
- Barbital Dose
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube (no anticoagulant) or serum separator tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Gas Chromatography-Mass Spectrometry (GC-MS) or Immunoassay
- SNOMED
- 387458009
- Specimen volume
- 2-5 mL of whole blood yielding 1-2 mL serum
- Stability
- Serum stable for 7 days at 2-8°C; for extended stability, store at -20°C for up to 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–96 hours
- Order
- routine
This test is a laboratory analysis performed on a sample of your blood, urine, or other body tissue. It helps your doctor measure specific substances in your body, check how well your organs are functioning, and gather important information about your overall health.
The Barbital [Mass] of Dose test measures the concentration of barbiturate drugs in your blood serum. Barbiturates are a class of medications that act as central nervous system depressants. They are prescribed for various conditions including seizure control, sedation, and anesthesia.
This test is performed to help diagnose a medical condition, monitor an existing illness, screen for disease before symptoms appear, or evaluate how well a treatment is working. Your doctor may also order it as part of a routine checkup to establish baseline values for your health.
This test is ordered by your doctor to: (1) Monitor therapeutic drug levels to ensure you are receiving the correct dose, (2) Detect potential drug toxicity or overdose, (3) Evaluate drug compliance, and (4) Guide dose adjustments based on individual response.
A trained healthcare professional will collect a small sample, most often by drawing blood from a vein in your arm using a sterile needle. The sample is then sealed, labeled, and sent to a laboratory, where specialized equipment and trained technologists analyze it and report the results to your doctor.
A blood sample will be drawn from a vein in your arm. For most accurate results, the sample is often collected just before your next dose (trough level) or as directed by your physician. The sample is then sent to a laboratory for analysis.
This test is generally very safe. If your blood is drawn, you may feel a quick sting when the needle is inserted, and mild bruising, soreness, or slight bleeding at the puncture site can occur. Serious complications such as infection are rare. Contact your doctor if the site becomes red, swollen, or painful.
Risks are minimal and include slight pain or bruising at the injection site, lightheadedness, or rarely, infection.
Reference range
Therapeutic range and dose mass are reported per individual dosing regimen; consult laboratory report for specific values relative to administered dose.N/A
No special patient preparation required. Sample should be collected at the appropriate post-dose interval as directed by the prescribing clinician.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Therapeutic drug monitoring (TDM) of barbiturates is crucial because the difference between effective and toxic doses can be narrow. Maintaining appropriate drug levels helps maximize therapeutic benefits while minimizing adverse effects such as drowsiness, respiratory depression, and in severe cases, coma or death.
Frequently asked questions
How should I prepare for this test?
What do the results mean?
What are the symptoms of barbiturate toxicity?
Sources
- 1
- 2
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 16, 2026. · Read our editorial policy