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Barbiturate (total) in serum/plasma by high-performance liquid chromatography (HPLC)

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

This test measures the total amount of barbiturates, a class of drugs used historically for sedation, anesthesia, or seizures, in your blood.

Quick summary

["Barbiturates can be detected in blood for several days after use and may affect your ability to think clearly or respond to your surroundings."]

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

Key facts at a glance

LOINC
12493-3
Short code
Hexobarbital SerPl-mCnc
Synonyms
Hexobarbital SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you’ve been exposed to barbiturates (e.g., through medication misuse, poisoning, or accidental ingestion) or if you’re experiencing symptoms like confusion, drowsiness, or breathing difficulties. It helps assess overdose risk or monitor treatment for conditions like epilepsy.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample drawn from a vein in your arm. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Higher-than-normal levels may indicate recent barbiturate exposure, while very low levels could suggest recent clearance from the body. Results are interpreted by your healthcare provider based on your symptoms and medical history.

Possible Side Effects or Risks

The blood draw is generally safe but may cause mild discomfort or bruising at the site. Rarely, overuse of barbiturates can lead to serious health risks, including respiratory depression or dependence.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Total Barbiturate Level

Frequently asked questions

What symptoms might this test help diagnose?
This test helps identify barbiturate poisoning or misuse, especially if you’ve experienced symptoms like drowsiness, slurred speech, or seizures. It’s also used in legal or forensic contexts to assess exposure.
How long will results take?
Results are typically available within 1–3 business days, depending on lab processing times. Your provider will discuss them with you during your follow-up visit.
Can I drink water before the test?
Yes, you can drink water unless instructed otherwise by your provider, as it’s not required for this test.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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