Clinically unexpected cyclosporine levels using the ACMIA method on the RXL dimension analyser

Safe use of cyclosporine (CsA) in solid organ transplantation relies on regular whole-blood drug monitoring. Several promising immmunoassays, e.g. the antibody-conjugated magnetic immunoassay (ACMIA) method, were developed and commercialized during recent years to compete with liquid chromatography coupled to tandem mass spectrometry, which remains the reference method but is labor-intensive. We describe the occurrence of interference in the monitoring of whole-blood CsA after transplantation when using the ACMIA method and discuss the potential mechanisms involved in such interference. Clinically unexpected results of whole-blood CsA require immediate reassessment by another technique to prevent the risk of CsA underdosage and graft rejection.