Barbitalserplscnc
This test measures the amount of barbital, a barbiturate medication, in your blood to ensure proper dosing and monitor for toxicity.
{"Barbital is a medication used to treat seizures, insomnia, and as a sedative","The test checks if the drug level in your blood is within the therapeutic range","Regular monitoring helps prevent dangerous side effects or overdose","Blood is drawn from a vein in your arm for this test","Results help your doctor adjust your medication dose if needed"}
Key facts at a glance
- LOINC
- 32050-7
- Short code
- BARB
- Synonyms
- Barbital SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube (no anticoagulant) or serum separator tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 50
- Critical range
- — – 150 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Gas Chromatography-Mass Spectrometry (GC-MS) or Immunoassay
- CPT
- 80345
- SNOMED
- 395171000119101
- Specimen volume
- 2-5 mL of whole blood yielding at least 1-2 mL serum
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The Barbital blood test measures the concentration of barbital in your serum or plasma. Barbital is a barbiturate—a type of prescription medication that acts as a central nervous system depressant. It is primarily used to control seizures, treat certain sleep disorders, and as a preoperative sedative.
Why do I need this test?
Your doctor may order this test for several reasons: to ensure you are taking the correct dose of barbital (therapeutic drug monitoring), to check for signs of drug toxicity, to evaluate if the medication is being metabolized properly, or to confirm compliance with your prescribed treatment. Maintaining the right level of barbital in your blood is important for effectiveness while minimizing side effects.
How is the test performed?
A healthcare professional will draw a small blood sample from a vein in your arm using a needle. The blood will be collected in a special tube and sent to a laboratory for analysis. The procedure typically takes only a few minutes. You may be asked to have your blood drawn at a specific time—often just before your next dose of medication—to get an accurate reading of the trough level (the lowest concentration in your blood).
What do the results mean?
Results are typically reported as a concentration (moles per liter). Your doctor will interpret your results based on the therapeutic range for barbital, which is generally between 65-130 micromoles per liter for seizure control. Levels below this range may indicate the dose is too low to be effective, while levels above may suggest toxicity. Your doctor will consider your symptoms, overall health, and other factors when interpreting your results.
Are there any risks?
The risks associated with this blood test are minimal and include minor bruising, bleeding, or soreness at the puncture site. In rare cases, fainting or infection may occur. The test itself does not carry significant risks since it only requires a small blood sample.
Reference range
Therapeutic range: 10-50 μmol/L (varies by laboratory and clinical context); generally not detected in unexposed individuals.N/A
No fasting required. Patient should be advised to inform the laboratory of all medications and supplements being taken prior to specimen collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Do I need to fast before this test?
How often will I need this test?
What can cause abnormal barbital levels?
Is barbital still commonly used?
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