When Hospital Toxicology Report Is Negative in a Suspected Overdosed Patient: Strategy of Comprehensive Drug Screen Using Liquid Chromatography Combined With Mass Spectrometry

Abstract

Abstract In general 9–10 drugs are routinely tested in most hospital laboratories and as a result many designer drugs escape detection. Moreover, compliance with benzodiazepine may not be monitored using routine benzodiazepine screen in urine using immunoassays due to poor cross-reactivity of many benzodiazepines with assay antibody as well as very poor cross-reactivity of glucuronide metabolite of lorazepam, temazepam, and other benzodiazepines. Moreover, compliance of patients with oxycodone therapy cannot be monitored by using opiate immunoassays because oxycodone has very poor cross-reactivity with opiate immunoassays although hydromorphone and hydrocodone may have some cross-reactivity. In general, other opioids such as propoxyphene, methadone, tramadol, fentanyl, etc. cannot be detected by opiate immunoassays, although specific immunoassays are available for some opioids. Therefore, if routine toxicology screen is negative in a suspected overdosed patient, then specimens should be sent to a reference laboratory capable of screening many drugs using liquid chromatography combined with tandem mass spectrometry.