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Barbituratesgastmcnc

Published: August 9, 2026Updated: August 17, 2026

This test measures the concentration of barbiturates in gastric fluid to detect drug overdose or poisoning.

Quick summary

{"Detects barbiturate drugs in stomach contents","Helps diagnose accidental or intentional overdose","Important for emergency toxicology assessment"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
9427-6
Short code
BARBGAS
Synonyms
Barbiturates Gast-mCnc
Category
chemistry
Sample
serum
Container
Sterile, leak-proof plastic container (gastric aspirate container); no preservative required
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunoassay or Gas Chromatography-Mass Spectrometry (GC-MS) confirmation
CPT
80345
SNOMED
39508000
Specimen volume
5-10 mL of gastric fluid
Stability
Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 30 days
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
2–24 hours
Order
routine

What is this test?

The Gastric Fluid Barbiturate test is a toxicology test that measures the presence and concentration of barbiturate drugs in stomach contents (gastric fluid). Barbiturates are a class of medications that act as central nervous system depressants, commonly used for sedation, anesthesia, and seizure control. This test uses mass spectrometry to identify and quantify barbiturate compounds in the sample.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No patient preparation required. Specimen is typically collected via gastric lavage or aspiration in suspected overdose cases. Document time of suspected ingestion and any treatment administered prior to collection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Why is gastric fluid tested instead of blood?
Gastric fluid testing is particularly useful in acute overdose cases because barbiturates are often present in high concentrations in the stomach, especially shortly after ingestion. It can help confirm the type and amount of drug consumed when blood tests may still be negative.
What do the results mean?
Results are reported as qualitative (present/absent) and quantitative (specific concentration). Therapeutic levels vary by specific barbiturate, while toxic levels typically cause significant sedation. Extremely high levels indicate potentially life-threatening overdose requiring immediate medical intervention.
Is special preparation needed?
No fasting or special preparation is required for this test. It is typically collected by healthcare professionals in emergency settings using gastric lavage (stomach pumping) or by collecting vomited material.
What conditions can cause false results?
Certain medications and substances may cross-react with the assay, potentially causing false-positive results. It is important to inform your healthcare provider about all medications, supplements, or substances you have recently consumed.
  1. 1
    MedlinePlus - Barbiturate ScreenSource
  2. 2
    Mayo Clinic Laboratories - BarbituratesSource

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 17, 2026. · Read our editorial policy