Drug Analyses in Poisoned Patients—The Need to Be Specific

Abstract

Methods for the qualitative determination of drugs in blood and urine which have been used over the past 20 years have on several occasions given rise to incorrect interpretation due to their lack of specificity, which has resulted in falsely high values being reported for commonly requested drugs. Modern methods provide an opportunity to ensure specificity in the future but analysts must continue to be aware of the potential pitfalls. Examples of non-specificity in colorimetric, UV spectrophotometric, and immunological techniques are described and the clinical implications are demonstrated.