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Barbituratesserplqlscn

Published: August 9, 2026Updated: August 16, 2026

A screening test to detect the presence of barbiturate drugs in your blood.

Quick summary

{"This test checks if barbiturate medications are in your blood","Barbiturates are drugs used for sedation, sleep, or seizure control","Results help doctors monitor drug levels or check for drug misuse","The test uses a blood sample from your vein","Positive results may need confirmatory testing"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
20421-4
Short code
BARBS
Synonyms
Barbiturates SerPl Ql Scn
Category
chemistry
Sample
serum
Container
Red-top serum tube or serum separator tube (SST); avoid gel separator for some immunoassays.
Units
N/A
Ref low
200
Ref high
300
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
screen
CPT
80307
SNOMED
16778006
Specimen volume
1-2 mL serum or plasma
Stability
Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
1–4 hours
Order
routine

What is this test?

The Barbiturate Screen test is a blood test that looks for barbiturates in your serum or plasma. Barbiturates are a class of prescription medications that act as central nervous system depressants. They are typically used for conditions such as anxiety, insomnia, seizure disorders, and as anesthesia during surgery.

Why do I need this test?

Your doctor may order this test for several reasons: to monitor the level of barbiturate medication in your blood to ensure it is within the therapeutic range; to check for accidental or intentional overdose; to evaluate symptoms of suspected barbiturate use or poisoning; or as part of a drug screening program for employment or medical purposes.

How is the test done?

A healthcare professional will draw a small amount of blood from a vein in your arm using a needle. The blood sample will be sent to a laboratory for analysis. The test is a screening method, which means it can indicate the presence of barbiturates but may not identify the specific type or exact amount.

What do the results mean?

A negative result means no barbiturates were detected in your blood at the time of testing. A positive result indicates that barbiturates are present in your blood. If the result is positive, your doctor may order additional tests to confirm the specific type and amount of barbiturate. It is important to discuss your results with your healthcare provider, as certain foods, medications, or supplements can sometimes cause false positive results.

Are there any risks?

The risks associated with this test are minimal and similar to any standard blood draw. You may experience slight pain, bruising, or bleeding at the puncture site. In rare cases, fainting or infection may occur. If you have a bleeding disorder or are taking blood thinners, inform your healthcare provider before the test.

Reference range

Negative (cutoff typically 200-300 ng/mL depending on assay)N/A

Specimen: serum

No special preparation required. Specimen should be collected prior to administration of emergency medications when possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

How long do barbiturates stay in your blood?
The detection window varies depending on the specific barbiturate, its dosage, and individual factors like metabolism and kidney function. Short-acting barbiturates may be detectable for 1-2 days, while long-acting ones like phenobarbital can be detected for up to 2-3 weeks after the last dose.
Can a barbiturate test show if I am taking my medication correctly?
Yes, this test can help determine if you are taking your prescribed barbiturate medication as directed. Therapeutic drug monitoring ensures the drug level is within the effective range—not too low to be ineffective, and not too high to cause toxicity.
Will a single dose of medication affect my test results?
Yes, even a single dose of a barbiturate medication can be detected in your blood, depending on the timing of the test relative to when you took the medication. Always inform your doctor about any medications, supplements, or herbs you are taking before the test.
What should I do if my test is positive?
If your test is positive, do not panic. Discuss the results with your prescribing doctor, who will interpret them in the context of your medical history and current treatment. If you are not prescribed barbiturates, your doctor will investigate further to determine the source of exposure.
Are there foods or substances that can cause a false positive?
Some substances may interfere with screening tests and cause false positive results. These may include certain antibiotics, antidepressants, or opioid medications. Always provide a complete list of all substances you have consumed to your healthcare provider for accurate interpretation.
  1. 1
    MedlinePlus - Barbiturate ScreenSource
  2. 2
    Mayo Clinic Laboratories - Barbiturates, Serum/PlasmaSource
  3. 3
    LabCorp - Barbiturate Screen, SerumSource

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.

Medical Disclaimer

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