Hematocrit-independent recovery of immunosuppressants from DBS using heated flow-through desorption.

Background: We applied our concept for automated flow-through desorption of DBS to investigate the effect of desorption temperature on recovery. For this purpose, a method has been developed for the determination of four immunosuppressants in DBS.

Results: We compared recoveries of four immunosuppressants for measurements with and without temperature-enhanced desorption at different hematocrit (Ht) levels. Temperature-enhanced desorption increased recovery substantially for tacrolimus, sirolimus and everolimus at all Ht values and for cyclosporine At high Ht. In addition, recovery became largely independent from Ht variations. Under the optimized conditions, a brief validation using spiked blood samples showed that the method complies with acceptance criteria for quantitative bioanalysis.

Conclusion: This method enables a quantitative analysis of immunosuppressants in DBS independent from the Ht.