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Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
The need for standardization of tacrolimus assays
Daniel M Levine1, Gregory T Maine, David A Armbruster
1Rogosin Institute, New York, NY, USA. dml9006@nyp.org
Clinical Chemistry
|October 15, 2011
Summary
Standardizing tacrolimus (immunosuppressant drug) assays is crucial due to significant variability in current testing methods. This study highlights the need for improved accuracy to ensure consistent patient care and optimized drug dosing globally.
Area of Science:
- Clinical Chemistry
- Pharmacology
- Analytical Chemistry
Background:
- Current monitoring of tacrolimus concentrations in whole blood lacks standardization due to the absence of an internationally recognized reference material and method.
- Existing liquid chromatography-mass spectrometry (LC-MS) and immunoassay methods exhibit significant variability, impacting patient care.
- This variability necessitates an assessment of the need for tacrolimus assay standardization.
Purpose of the Study:
- To evaluate the current state of tacrolimus assay standardization across different clinical laboratories and methodologies.
- To determine the extent of variability in tacrolimus measurements using common clinical assays.
- To establish the necessity of standardization for accurate tacrolimus monitoring.
Main Methods:
- A blinded proficiency panel of whole-blood tacrolimus samples (0-30 μg/L) was distributed to 22 clinical laboratories in 14 countries.
- Participating laboratories utilized Abbott ARCHITECT, LC-MS, and Siemens Dade Dimension assays.
- Reference values were established using isotope-dilution mass spectrometry; LC-MS results were compared to a validated method, with some LC-MS sites receiving a common calibrator set.
Main Results:
- Coefficient of variation (CV) ranges varied significantly across assays: LC-MS (11.4%-18.7%), ARCHITECT (3.9%-9.5%), and Siemens Dade (5.0%-48.1%).
- Historical within-site quality control CVs also showed considerable variation, particularly for the Siemens Dade Dimension assay.
- The use of a common calibrator set did not correct assay bias observed among LC-MS sites.
Conclusions:
- Tacrolimus assay standardization is essential for reliable comparison of patient results across clinical laboratories.
- Enhanced assay accuracy is imperative for optimizing drug dosing and ensuring consistent patient care in transplant centers worldwide.
- The study underscores the urgent need for standardized methods in therapeutic drug monitoring of tacrolimus.
