Answer
From http://64.233.167.104/search?q=cache:updrz4dacjwj:www.tiaft.org/tiaft2001/lectures/l13_gerostamoulos.doc+elisa+forensic&hl=en&ct=clnk&cd=1&gl=us&client=firefox-a"elisa is a quick and convenient method for the analysis of drugs in blood and even tissue homogenates. this has been shown to achieve sensitivities and specificities comparable with those of radioimmunoassays, and has the advantage of automation (1,2). elisa analysis for postmortem blood specimens has been shown to be useful in our laboratory. "more on elisa from http://en.wikipedia.org/wiki/elisa:"enzyme-linked immunosorbent assay, or elisa, is a biochemical technique used mainly in immunology to detect the presence of an antibody or an antigen (like a drug or poison) in a sample. the elisa has been used as a diagnostic l in medicine and plant pathology, as well as a quality control check in various industries. in simple terms, in elisa an unknown amount of antigen is affixed to a surface, and then a specific antibody is washed over the surface so that it can bind to the antigen. this antibody is linked to an enzyme, and in the final step a substance is added that the enzyme can convert to some detectable signal. thus in the case of fluorescence elisa, when light is shone upon the sample, any antigen/antibody complexes will fluoresce so that the amount of antigen in the sample can be measured."
