[Skip to Content]
[Skip to Content Landing]
January 1979

A Rapid and Sensitive Radioreceptor Assay for Benzodiazepine in Plasma

Author Affiliations
From the Laboratory of Preclinical Studies, National Institute of Alcohol Abuse and Alcoholism, Rockville, Md (Dr Skolnick) and the Clinical Psychobiology Branch, National Institute of Mental Health, Bethesda, Md (Drs Goodwin and Paul).
Arch Gen Psychiatry. 1979;36(1):78-80. doi:10.1001/archpsyc.1979.01780010084009

• We describe a rapid and sensitive radioreceptor assay for measuring benzodiazepines in plasma. This method is based on the competition between tritiated diazepam and pharmacologically active benzodiazepines present in plasma, for binding sites on rat brain synaptosomal membranes. No interference is obtained with drug-free plasma or plasma samples containing high concentrations of other commonly used drugs. High correlations (r = 0.98; P <.001) were obtained between the "diazepam equivalents" measured in plasma with the radioreceptor assay and the levels of diazepam and nordiazepam obtained by gas-liquid chromatography. The radioreceptor assay is rapid, sensitive, specific, and requires no sophisticated equipment or methods. It should therefore prove useful in monitoring blood benzodiazepine levels for both therapeutic and toxicologic purposes.