Complete Blood Count (CBC)
This test detects the presence of barbiturate drugs in your blood to monitor medication levels or check for overdose.
{"Detects barbiturate drugs (sedatives, seizure medications) in blood","Used to monitor proper medication dosing or detect poisoning","Commonly prescribed barbiturates include phenobarbital and pentobarbital","Results help doctors ensure safe and effective treatment","Sample is collected from a vein in your arm"}
Key facts at a glance
- LOINC
- 3376-1
- Short code
- BARB
- Synonyms
- Barbiturates SerPlBld Ql
- Category
- chemistry
- Sample
- serum
- Container
- Red-top vacutainer tube (no anticoagulant) for serum; or lavender-top (EDTA) tube for plasma; or gray-top (sodium fluoride/potassium oxalate) tube for blood
- Units
- N/A
- Ref low
- 0
- Ref high
- 200
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (e.g., EIA, FPIA) with confirmatory Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 80345
- SNOMED
- 33351009
- Specimen volume
- 5-10 mL of whole blood; minimum 1-2 mL of serum or plasma required
- Stability
- Serum/plasma stable at room temperature for 24 hours, refrigerated (2-8°C) for 7 days, and frozen (-20°C or below) for 30 days. Protect from light.
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 4–72 hours
- Order
- routine
What is a complete blood count (CBC) and what does this test measure in my blood?
The Barbiturates test looks for barbiturate drugs in your blood serum, plasma, or whole blood. Barbiturates are prescription medications that slow down brain activity. They are commonly used to treat seizures (like phenobarbital), severe anxiety, and as sedatives before surgery. This test helps your doctor know if you have the right amount of medication in your system.
Why might my healthcare provider order a complete blood count (CBC) test for me?
Your doctor may order this test for several reasons: to make sure you are taking the correct dose of your barbiturate medication, to check if you have taken too much of the drug (overdose), or to investigate unexplained symptoms like extreme drowsiness, confusion, or breathing problems. It may also be used in emergency situations if poisoning is suspected.
How is a complete blood count (CBC) test performed, and how should I prepare for it?
A healthcare professional will draw a small blood sample from a vein in your arm using a needle. The sample is then sent to a laboratory for analysis. You may need to avoid taking your barbiturate medication until after the test if your doctor instructs you to do so. Follow any specific instructions given by your healthcare provider.
What do the results of a complete blood count (CBC) test mean for my health?
A negative result means no barbiturates were detected in your blood. A positive result means barbiturates were found. Your doctor will interpret the results based on your medical history, the specific barbiturate you are taking, and your symptoms. Therapeutic levels vary depending on the medication and what condition is being treated.
Reference range
Negative: Cutoff concentration typically <200 ng/mL (varies by laboratory and assay). Positive results indicate the presence of barbiturates above the established cutoff threshold.N/A
No fasting required. Patients should be informed that certain prescription and over-the-counter medications may contain barbiturates. Inform the clinician of all medications being taken prior to testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is clinically important for monitoring patients taking barbiturate medications to ensure they are receiving therapeutic (effective) doses without reaching toxic levels. It helps diagnose barbiturate overdose or poisoning, which can cause dangerous symptoms like slowed breathing, loss of consciousness, and in severe cases, coma or death. The test is also valuable in emergency and forensic settings when unexplained sedation or drug toxicity is suspected.
Frequently asked questions
Will I feel any pain during the test?
How long does it take to get results?
Do I need to fast before this test?
Are there any risks with this test?
What should I tell my doctor before the 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 14, 2026. · Read our editorial policy