Complete Blood Count (CBC): What It Is and Why It Matters
A screening test to detect the presence of barbiturates (sedative medications) in your blood or body fluid.
{"This test checks if barbiturate medications are present in your body","It helps doctors monitor proper medication levels or detect possible overdose","Results are typically reported as positive or negative","Follow your doctor's instructions about taking medications before the test"}
Key facts at a glance
- LOINC
- 91028-1
- Short code
- BARTBS
- Synonyms
- Barbiturates Fld Ql Scn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top vacuum tube (no anticoagulant) for serum; alternatively, serum separator tube (SST)
- Units
- N/A
- Ref low
- 3.5
- Ref high
- 7.2
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- screen
- CPT
- 80307
- SNOMED
- 395112001
- Specimen volume
- 1-2 mL of serum
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 2–24 hours
- Order
- routine
A complete blood count, or CBC, is a common blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets, to give your care team a clear picture of your overall health.
The barbiturates test is a screening method that detects whether barbiturate drugs are present in your body fluid (such as blood/serum). Barbiturates are a class of sedative-hypnotic medications that were historically used for sedation, sleep disorders, and seizure control. Examples include phenobarbital, pentobarbital, and secobarbital.
A healthcare professional will draw a small sample of blood, usually from a vein in your arm, using a thin needle. The sample is then sent to a laboratory for analysis, and the blood draw itself typically takes only a few minutes.
A healthcare professional will collect a sample of your blood (serum) from a vein in your arm. The sample is then sent to a laboratory where it is tested using screening methods, typically immunoassay techniques, to detect the presence of barbiturates.
Your doctor may order a CBC as part of a routine checkup or to help diagnose conditions such as anemia, infection, inflammation, or blood disorders. It can also be used to monitor an existing condition or to see how well a treatment is working.
Your doctor may order this test for several reasons: (1) to monitor the level of barbiturate medication you are taking for seizure control or other medical conditions, (2) to check for signs of drug overdose or toxicity, (3) to evaluate unexplained symptoms like excessive drowsiness, confusion, or breathing problems, or (4) as part of a drug screening in certain clinical situations.
In most cases, no special preparation is needed for a CBC, and you can eat and drink normally beforehand. If other tests require fasting, your doctor will let you know. Tell your care team about any medications, vitamins, or supplements you take, and mention if you have ever felt faint during blood draws.
Follow your doctor's instructions regarding taking your prescribed barbiturate medications before the test. Do not stop taking prescribed medications unless your doctor tells you to. Inform your doctor about all medications, supplements, and herbal products you are taking, as some substances may affect test results.
Reference range
NCBI: Uric Acid Male 3.5-7.2 mg/dL; Female 2.5-6.8 mg/dLN/A
No fasting required. Patient should be informed that barbiturates may be prescribed medications or drugs of abuse. Specimen collection should follow chain-of-custody procedures if used for forensic or medicolegal purposes.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is important for therapeutic drug monitoring (TDM) in patients taking barbiturates for epilepsy or other conditions. Proper dosing is critical because the difference between a therapeutic dose and a toxic dose can be small. The test helps ensure drug levels are within the therapeutic range and not reaching toxic levels. A positive result may indicate proper medication adherence, but very high levels may suggest overdose, which can cause serious symptoms like severe drowsiness, respiratory depression, or even coma. In emergency settings, this test helps guide treatment for suspected barbiturate overdose.
Frequently asked questions
Will the test tell me how much medication is in my system?
How long do barbiturates stay in my system?
Are there any risks from this test?
What do the results mean?
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 17, 2026. · Read our editorial policy