Testing is often conducted in clinical, forensic, or toxicological settings to detect the presence of barbiturates in blood, urine, or other biological samples.

1. Purpose of the Test:

• Clinical Use: To monitor therapeutic levels in patients using barbiturates for medical reasons, ensuring they remain within a safe range.
• Toxicology: To confirm barbiturate overdose or poisoning in suspected cases of substance misuse or self-harm.
• Forensic Applications: To investigate causes of death or impairment in legal cases.

1. Testing Methods:

• Immunoassay: A preliminary screening method used for rapid detection of barbiturates in urine.
• Gas Chromatography-Mass Spectrometry (GC-MS): A confirmatory test used to identify specific barbiturates and quantify their levels.
• High-Performance Liquid Chromatography (HPLC): Another method for precise quantification in biological samples.

1. Interpretation of Results:

• Therapeutic levels depend on the specific barbiturate and its prescribed dose. For example:
• Phenobarbital: 10–40 µg/mL (therapeutic range in plasma).
• Toxic levels can lead to respiratory depression, coma, or death.
• Chronic use may lead to tolerance and dependence.