Interlaboratory comparison study of immunosuppressant analysis using a fully automated LC-MS/MS system

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Pharmacology

Background:

• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is recommended for immunosuppressant quantification but limited by method complexity and lack of harmonization.
• Immunoassays are widely used despite LC-MS/MS superiority due to practical challenges.
• A fully automated LC-MS/MS system (Cascadion™) aims to simplify clinical application.

Purpose of the Study:

• To evaluate the interlaboratory comparability of immunosuppressant assays using the automated Cascadion™ LC-MS/MS system.
• To assess the impact of sample handling procedures (freezing/thawing, primary vs. secondary tubes) on assay results.

Main Methods:

• Three European centers performed interlaboratory comparisons on 1097 whole blood samples.
• Samples were shared between sites to assess method agreement.
• Experiments included freeze-thaw stability and primary vs. secondary tube analysis.

Main Results:

• Excellent correlation coefficients (0.990-0.993) were observed for cyclosporine A, everolimus, sirolimus, and tacrolimus.
• Minimal average bias was found for tacrolimus in fresh vs. frozen samples (0.36%) and primary vs. secondary tubes (1.14%).

Conclusions:

• The automated Cascadion™ platform achieves a high level of result harmonization for LC-MS/MS immunosuppressant analysis.
• This system facilitates the routine clinical use of LC-MS/MS for accurate immunosuppressant monitoring.