Understanding Your Laboratory Test: A Patient Guide to Testing, Procedure, and Results
This test measures the amount of barbital, a barbiturate medication, in your urine to monitor treatment or check for drug use.
{"Barbital is a sedative medication sometimes used for anxiety or sleep problems","This test uses urine to check if barbital is present in your body","It may be ordered to monitor safe medication levels or check for drug compliance","The test uses a confirmatory method for accurate results","Follow your doctor's instructions about taking medications before the test"}
Key facts at a glance
- LOINC
- 20518-7
- Short code
- BARBU
- Synonyms
- Barbital Ur Cfm-mCnc
- Category
- chemistry
- Sample
- urine
- Container
- Sterile, leak-proof urine collection container without preservatives; screw-cap plastic container
- Units
- N/A
- Ref low
- 0
- Ref high
- 50
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- confirm
- CPT
- 80307
- SNOMED
- 250657005
- Specimen volume
- 10-30 mL random urine specimen; minimum 5 mL required
- Stability
- Stable for 7 days at 2-8°C; stable for 1 month at -20°C; room temperature stability limited to 48 hours
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
This test is a medical laboratory procedure that helps your healthcare provider evaluate your health. It measures specific substances or markers in a sample from your body, such as blood or urine, to check how well certain organs and body systems are working.
The Barbital Urine Test measures the amount of barbital in your urine. Barbital is a barbiturate, a type of sedative (calming) medication that was historically used to treat anxiety, insomnia (trouble sleeping), and certain seizure disorders. This test uses a confirmatory method, which is a highly accurate laboratory technique to identify and measure specific drugs in your sample.
Your provider may order this test to help find the cause of symptoms you are having, to screen for a condition before it causes problems, to monitor a disease you already have, or to see how well a treatment is working for you over time.
Your healthcare provider may order this test for several reasons: to monitor if you are taking your prescribed barbital medication at the correct level, to check for drug compliance (making sure you are taking your medicine as directed), or in some cases, as part of a drug screening program. Barbital is now less commonly prescribed due to the availability of safer alternatives, so this test may also be used in special monitoring situations.
The test is usually done by collecting a small sample, most often blood drawn from a vein in your arm with a fine needle. The sample is then sent to a laboratory where trained staff analyze it. The procedure is typically quick, and you can usually go home right afterward.
A urine sample is collected in a clean container. You will be given instructions on how to collect the sample properly. The sample is then sent to a laboratory where it is analyzed using a confirmatory method, such as mass spectrometry, which can accurately identify and measure barbital even at very low levels. This is more specific than simple screening tests.
Your results show whether your values fall within the normal reference range. Normal results may suggest no sign of the condition being tested, while abnormal values can point to an infection, inflammation, organ problem, or other issue that needs a closer look. Always review your results with your provider to understand what they mean for you.
Your test results will show whether barbital was detected in your urine and possibly how much was present. Your healthcare provider will interpret these results based on your medical history, why the test was ordered, and other factors. It is important to discuss your results with your doctor, who can explain what they mean for your specific health situation.
Reference range
Negative (below limit of detection, typically <50 ng/mL). Therapeutic and toxic ranges vary; consult laboratory-specific reference values.N/A
No fasting required. Patient should be informed that this is a confirmatory drug test. Collect specimen under chain-of-custody procedures if required for forensic or workplace drug testing purposes.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The Barbital Urine Test is clinically significant for therapeutic drug monitoring, ensuring patients maintain appropriate medication levels for treatment efficacy while avoiding toxicity. It helps healthcare providers verify medication compliance, which is important for safe and effective treatment. The confirmatory method used (typically gas chromatography-mass spectrometry or liquid chromatography-tandem mass spectrometry) provides highly specific and accurate results, reducing false positives that might occur with simpler screening tests. This is particularly important in monitoring patients on long-term barbiturate therapy.
Frequently asked questions
Do I need to fast before this test?
Will the test hurt?
How long does it take to get results?
Can medications affect the test results?
Is this test the same as a drug screening test?
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