Euromedlab: CONFIDENCE IN YOUR CALIBRATORS: ASSESSMENT OF MASSTRAK TM IMMUNOSUPPRESSANT CALIBRATOR AND CONTROL SETS

Importance of the Topic

Reliable quantification of immunosuppressant drugs such as cyclosporine, everolimus, sirolimus and tacrolimus is critical for therapeutic drug monitoring and patient safety. Variability and cross-reactivity in immunoassays can lead to inaccurate dosing decisions, whereas LC-MS/MS offers greater specificity and sensitivity. However, laboratories need metrologically traceable calibrators and quality control materials to ensure consistent, harmonized results and compliance with ISO 15189 requirements.

Objectives and Study Overview

This study evaluates the performance of the Waters™ MassTrak™ Immunosuppressant Calibrator and Quality Control Sets (IVD) in an in-house LC-MS/MS method. The main goals were to assess precision, repeatability, accuracy, analytical sensitivity, linearity and agreement with external quality assessment (EQA) samples across four key immunosuppressant drugs.

Methodology and Instrumentation

Sample Preparation:

• Aliquot 50 µL whole blood into 96-well plates.
• Add 200 µL 0.1 M aqueous zinc sulfate, mix 5 s; add 500 µL internal standard, mix 20 s; centrifuge 2 min at 4 969 g.

Chromatography and Detection:

• Waters ACQUITY UPLC I-Class FL system with a 2.1 × 30 mm ACQUITY UPLC HSS C18 SB column.
• Gradient of water/methanol/ammonium acetate/formic acid, positive-mode ESI.
• Waters Xevo TQ-S micro detector operated in MRM mode, analyzing ammoniated adducts with quantifier, qualifier and internal standards for each analyte.
• Load-Ahead function enabled, average injection-to-injection time ~1.9 minutes.

Calibrators and Controls:

• Pre-weighed, lyophilized whole-blood calibrators and tri-level QC sets containing each drug.
• Traceable to primary reference materials to support ISO 15189 compliance.

Key Results and Discussion

Precision and Repeatability:

• Total precision and repeatability across five days (n = 25) for QC sets were ≤ 7.1% CV.

Analytical Sensitivity and Linearity:

• Signal-to-noise ratios (peak-to-peak) for the lowest calibrator exceeded 10 for all four drugs.
• Calibration curves exhibited mean r2 > 0.999, demonstrating excellent linearity across clinical ranges.

Accuracy and EQA Agreement:

• QC accuracy relative to certified values ranged from 94.5 – 103.6%.
• Mean bias for external quality assessment samples was within ± 7.4% for all analytes.

Time and Resource Efficiency:

• Pre-prepared calibrators and controls significantly reduce labor and potential errors compared to in-house preparation.

Benefits and Practical Applications

• Metrologically traceable calibrators support method validation and accreditation.
• Lot-to-lot consistency improves longitudinal monitoring and inter-laboratory harmonization.
• Rapid sample turnover (~1.9 min per injection) enhances throughput in clinical and research laboratories.
• Reduction in hands-on preparation and error risk streamlines workflow.

Future Trends and Potential Applications

With growing adoption of LC-MS/MS for therapeutic drug monitoring, next-generation calibrators may incorporate additional analytes or isotopically labeled standards for emerging biomarkers. Automation of sample preparation and integration with laboratory information systems will further improve efficiency. Enhanced EQA schemes and data analytics could enable real-time performance monitoring and inter-laboratory comparison.

Conclusion

The Waters MassTrak Immunosuppressant Calibrator and QC Sets deliver robust, traceable performance in LC-MS/MS assays for key immunosuppressants. They demonstrate excellent precision, sensitivity, linearity and accuracy, while reducing preparation time and supporting ISO 15189 compliance. These materials offer a reliable solution for laboratories seeking harmonized, high-throughput drug monitoring.

Reference

No external references were provided in the source document.