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Barbiturate (total) in serum/plasma

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

This test measures the amount of barbiturate drugs in your blood, which may be used to monitor levels after treatment for conditions like seizures or overdose.

Quick summary

["This test helps doctors check if your barbiturate medication is at an appropriate level for your needs."]

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

Key facts at a glance

LOINC
4028-7
Short code
Secobarbital SerPl-mCnc
Synonyms
Secobarbital 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 This Test Is Done

Your healthcare provider may order this test if you’re taking barbiturate medications (e.g., phenobarbital) to manage conditions like epilepsy or to treat severe overdoses. It helps ensure your medication is working safely and at the right dose.

What to Expect Before the Test

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

What the Results Mean

Results show the total concentration of barbiturates in your blood. High levels may indicate overdose or improper dosing, while low levels could mean your medication isn’t effective. Your provider will interpret results in the context of your medical history and treatment plan.

Possible Causes of Abnormal Results

High barbiturate levels might be due to overdose, improper dosing, or liver/kidney issues affecting drug clearance. Low levels could suggest poor absorption or rapid metabolism. Always discuss results with your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Barbiturates are central nervous system depressants used historically for seizures or sedation. Chronic exposure or high doses can lead to toxicity, affecting breathing, heart rate, or consciousness. Regular monitoring is critical for patients on long-term use.

Short name

Total Barbiturate Level

Frequently asked questions

Why might my barbiturate levels be checked regularly?
Regular checks help prevent toxicity (e.g., drowsiness, confusion) or ensure the drug remains effective. Your doctor may adjust doses based on these results.
What should I do if my barbiturate levels are too high?
Seek immediate medical attention. High levels can be life-threatening and require urgent treatment, such as supportive care or antidotes.
Can diet or other medications affect barbiturate levels?
Yes, certain foods, liver enzymes, or other drugs (e.g., antacids) may influence how your body processes barbiturates. Always inform your provider about all medications or supplements you take.
  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