Comparison Between an Automated and Manual Extraction for the Determination of Immunosuppressive Drugs Whole Blood Concentrations by Liquid Chromatography Tandem Mass Spectrometry.

BACKGROUND: The whole blood extraction for liquid chromatography tandem mass spectrometry (LC-MS/MS) of simultaneous quantification of cyclosporine A (Cys A), tacrolimus (Tacrs), sirolimus (Siros), and everolimus (Evers) is still performed manually in many laboratories. The analytical results obtained with an automated method using a liquid handler versus a classical manual preparation were compared. METHODS: Cys A (n = 36), Tacrs (n = 50), Siros (n = 34), Evers (n = 38) whole blood samples of patients were analyzed by LC-MS/MS assay after manual preparation and automated process using a liquid handling platform including a centrifugation step. RESULTS: The comparison between manual and automated extraction investigated by a linear regression showed a high correlation between results [(Tacrs "automated") = 1.0927 × (Tacrs "manual") - 0.36; (Cys A "automated") = 1.0284 × (Cys A "manual") + 0.0312; (Siros "automated") = 0.9923 × (Siros "manual") + 0.4001; (Evers "automated") = 1.0000 × (Evers "manual") - 0.0600]. CONCLUSION: The results obtained by the automated and manual preparation are consistent. The automated method is applied for high-throughput therapeutic drug monitoring of immunosuppressive drugs in routine practice, leading to an increase in quality.

Evaluation of a Methotrexate Chemiluminescent Microparticle Immunoassay: Comparison to Fluorescence Polarization Immunoassay and Liquid Chromatography-Tandem Mass Spectrometry.

OBJECTIVES: For most laboratories, methotrexate (MTX) concentrations are routinely monitored by fluorescence polarization immunoassay (FPIA). In anticipation of an announced withdrawal of the FPIA reagent on the Abbott TDxFLx (Abbott Diagnostics, Abbott Park, IL), we have evaluated a new reagent kit developed by Abbott on the Architect i1000, based on chemiluminescent microparticle immunoassay (CMIA). METHODS: Precision, inaccuracy, and selectivity were assessed. Interassay variability was established using 75 plasma patient samples treated with MTX and analyzed by two methods: FPIA and liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS FOR MTX,: the intraday inaccuracy was between -6.37% and +3.52%, while interday performance was between -3.70% and 7.90%. Intraday and interday imprecision was less than 2.65% and less than 2.22%, respectively. The correlation coefficient between CMIA and FPIA or LC-MS/MS was 0.9969 and 0.9985, respectively. CONCLUSIONS: These results comparing CMIA vs FPIA and LC-MS/MS indicate that CMIA is a suitable alternative to the FPIA method.