MSACL 2023 Abstract

Introduction:
The dried blood spot (DBS) sampling technique is advantageous over the traditional liquid blood collection due to its minimal invasiveness, smaller sample volume, improved analyte stability, and ease of storage and transportation, resulting in its increasing usage in therapeutic drug monitoring and clinical toxicology. Here, we describe a fully automated workflow to rapidly extract and quantify a wide range of therapeutic drugs and drugs of abuse in DBS using the Thermo Scientific™ Transcend™ DSX-1 UHPLC system, fulfilling routine drug monitoring needs in clinical laboratories.

Method:
Calibrators in blood are spotted on the DBS cards; analytes are extracted from the cards in an automated fashion using innovative flow-through desorption (FTD™) technology, and their corresponding internal standards (IS) are introduced via an automated IS addition module in the dried spot autosampler. Two-dimensional TurboFlow technology allows the removal of interferences from the extracted samples before analytical separation. An integrated software controls every step of the sample desorption and separation. Analyte quantitation is performed on the Thermo Scientific™ TSQ Altis™ Plus triple quadrupole mass spectrometer, and the data is analyzed in Thermo Scientific™ TraceFinder™ software.

Results:
A total of 77 therapeutic and clinical toxicology drugs from 11 compound classes, including anticonvulsants, antidepressants, antihistamines, antipsychotics, benzodiazepines, cocaine, dissociatives, opioids, and stimulants, are quantified in a single injection from DBS cards using a rapid automated method on a Transcend DSX-1 system. The Transcend DSX-1 system combines a dried spot module for direct analyte extraction with a UHPLC for online sample separation using TurboFlow technology. The method only takes 4.3 minutes from analyte extraction to MS detection. Good calibration curves with R2 > 0.98 are achieved using a weighting factor of 1/x, and the limit of quantification (LOQ) values are established with % RSD and % CV < 15, │% Diff│ < 20, and relative ion ratio < %20. The LOQ values are all in the low ng/mL levels, which largely meet the screening and confirmation sensitivity needs of analytical methodologies in routine clinical laboratories.

Conclusion:
Transcend DSX-1 combines a dried spot autosampler and TurboFlow LC-MS/MS and provides a complete workflow for fast and robust quantification of 77 therapeutical drugs and drug-of-abuse analytes in dried blood spots.