Development and evaluation of a radioimmunoassay for the analysis of body fluids to determine the presence of tricyclic antidepressant drugs

Abstract

A radioimmunoassay has been developed for the direct detection of tricyclic antidepressant drugs in blood and urine. It is based on a radioiodinated derivative of desipramine and this allows the use of relatively simple gamma-counting procedures. The assay can detect low concentrations (50–500 ng ml^–1, depending on the drug) in very small amounts (50 µl) of blood and urine. It is reliable, cheap, rapid, simple to perform and biological samples can be assayed directly. The antiserum is availáble commercially and the radiolabelled desipramine is easy to prepare. The assay is group specific, is well suited to the task of screening large numbers of samples and is now in routine use in several forensic science laboratories.