A multi-analyte approach to help in assessing the severity of acute poisonings - Development and validation of a fast LC-MS/MS quantification approach for 45 drugs and their relevant metabolites with one-point calibration

Diagnosis, monitoring of the efficiency of detoxification, and estimating the prognosis of acute poisonings are important tasks in emergency toxicology. Comprehensive screening and quantification of relevant substances by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS) help in assessing the severity of most acute poisonings. Turnaround time for such analyses must be short enough to impact on clinical decisions. Therefore, a multi-analyte LC-MS/MS approach with a 5-minute gradient was developed and validated for 45 drugs and their active metabolites as a complement to an existing GC-MS approach using the same liquid-liquid extraction. The determination ranges were defined by quality control samples of low and high, representing concentrations from low therapeutic to highly toxic levels. To shorten the turnaround time, one-point calibration was used. Validation showed low matrix effects and ionization effects of co-eluting analytes thanks to APCI source as well as sufficient recoveries, precisions, and selectivities. For accuracy, 32 of the 45 compounds fulfilled the criteria for quantification in lower therapeutic and 41 in overdosed and toxic concentrations, considering limits of +/- 30% deviation. The reuse of the processed calibrator for a period of 30days was possible for 32 compounds, showing sufficient stability at 8 degrees C. In addition, analysis of authentic blood samples showed the applicability and yielded drug levels, which were comparable to those determined by fully validated therapeutic drug monitoring methods. In conclusion, the present approach in combination with the GC-MS approach should provide sufficient support for clinical assessment of the severity of poisonings with 68 compounds in an acceptable turnaround time.