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Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
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Results From a Proficiency Testing Pilot for Immunosuppressant Microsampling Assays
Herman Veenhof1,2, Remco A Koster1,3, Lenneke A T Junier1
1Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
Therapeutic Drug Monitoring
|August 16, 2022
Summary
Microsampling for immunosuppressant drug monitoring shows significant lab variation, impacting clinical decisions. Standardization and regular proficiency testing are crucial for reliable home-based blood collection in transplant patients.
Area of Science:
- Clinical Chemistry
- Pharmacology
- Transplantation Medicine
Background:
- Therapeutic drug monitoring (TDM) of immunosuppressants is vital for preventing allograft rejection in transplant recipients.
- Home-based microsampling via fingerprick offers patient convenience, with samples mailed to laboratories.
- This study piloted an external quality control program for immunosuppressant microsampling.
Purpose of the Study:
- To pilot an external quality control program for immunosuppressant microsampling.
- To assess interlaboratory variation in microsampling techniques.
- To evaluate the impact of microsampling on clinical decision-making.
Main Methods:
- 14 laboratories across 7 countries participated in 3 proficiency testing rounds.
- Tested immunosuppressants included tacrolimus, ciclosporin, everolimus, sirolimus, and mycophenolic acid.
- Microsampling devices (Whatman, HemaXis, Mitra, Capitainer-B) and liquid chromatography-tandem mass spectrometry assays were used.
Main Results:
- Imprecision (CV%) for tacrolimus microsamples ranged from 11.7%-18.6% across rounds.
- Liquid whole blood samples showed lower imprecision (3.9%-4.9%) in round 2.
- Significant interlaboratory variation in analytical procedures, especially extraction, was observed.
Conclusions:
- Immunosuppressant microsampling methods exhibit substantial interlaboratory variability compared to whole blood methods.
- This variation can affect clinical decisions, highlighting the need for harmonization and standardization.
- Regular proficiency testing is essential for laboratories utilizing immunosuppressant microsampling in patient care.
