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

Importance of the topic

Accurate measurement of immunosuppressant drugs such as cyclosporine, everolimus, sirolimus, and tacrolimus is critical for patient care in transplant medicine. Traditional immunoassays suffer from cross-reactivity and limited sensitivity at low concentrations. Transitioning to LC-MS/MS enhances specificity, sensitivity, and confidence in therapeutic drug monitoring results.

Objectives and Overview of the Study

This study evaluates the performance of the MassTrak Immunosuppressant Calibrator and Quality Control Sets. Key objectives:

• Assess calibration linearity and sensitivity for four immunosuppressants
• Determine precision, repeatability, and accuracy of QC materials
• Verify compliance with ISO 15189 via metrological traceability
• Compare resource and time savings against in-house preparation workflows

Methodology

Sample Preparation:

• 50 µL of whole blood per well in a 96-well plate
• Add 200 µL of 0.1 M zinc sulfate for protein precipitation
• Add 500 µL of internal standard, mix, and centrifuge at 4969g for 2 minutes
• Inject supernatant directly for analysis

Calibration & QC:

• Lyophilized whole blood calibrators reconstituted to yield traceable concentrations
• Tri-level QC materials extracted and analyzed in five replicates over five days (n=25)

Used Instrumentation

• Waters ACQUITY UPLC I-Class System with HSS C18 SB Column (2.1×30 mm)
• Waters ACQUITY UPLC I-Class Focus System and gradient pump
• Waters Xevo TQ-S micro Mass Spectrometer in positive ESI MRM mode

Main Results and Discussion

Calibration Performance:

• Baseline separation achieved for all four drugs in a 1.9-minute run
• S/N >10 (peak-to-peak) for the lowest calibrator level
• Linearity with r2 >0.999 across calibration ranges

Precision & Accuracy:

• Total precision and repeatability ≤7.1% CV across five analytical runs
• QC accuracy relative to certified values between 94.5% and 103.6%
• External quality assessment bias within ±7.4% for all analytes

Benefits and Practical Applications

• Metrological traceability supports ISO 15189 accreditation
• Lot-to-lot consistency enhances long-term method stability
• Pre-weighed, ready-to-use materials reduce hands-on preparation time
• Improved confidence and reproducibility in immunosuppressant monitoring

Future Trends and Potential Applications

As LC-MS/MS adoption grows, future developments may include:

• Automation of sample preparation for higher throughput
• Expansion to additional therapeutic drugs or metabolites
• Integration with laboratory information systems for streamlined data management
• Advances in multiplexed assays and nano-LC technologies

Conclusion

The MassTrak Immunosuppressant Calibrator and Quality Control Sets deliver consistent, traceable, and accurate materials for LC-MS/MS assays. Their use enhances laboratory efficiency, ensures compliance with international standards, and provides robust performance for therapeutic drug monitoring of immunosuppressants.

Reference

• Waters Corporation. Assessment of MassTrak Immunosuppressant Calibrator and Control Sets. Application Note 720007583; 2023.