title: Clinical significance of hematocrit interference in the tacrolimus II microparticle enzyme immunoassay: a tentative approach.
abstract: Recently, the possible interference of hematocrit on the results of the Abbott Tacrolimus II microparticle enzyme immunoassay (MEIA) has been described, although its significance in clinical practice has not been established as yet. The aim of our study was the evaluation of the significance of this analytical interference in therapeutic tacrolimus monitoring. In 1121 cases selected at random over a 9-month period from kidney (n=379) and liver (n=742) transplant patients, an estimation was made of errors caused by the hematocrit in the results provided by the Tacrolimus II MEIA. In accordance with the available data, it was assumed that an error may be produced beyond the range of hematocrit values from 30% to 40%, either positive or negative respectively, of 3% per unit of hematocrit. The acceptance criterion for accuracy was no more than 15% of deviation (error) with respect to the experimental concentration of tacrolimus. In 160 cases (14.3%) the results of the Tacrolimus II MEIA would not be acceptable due to hematocrit-dependent errors, both with positive (hematocrit <25%) in 108 cases (9.7%) and negative values (hematocrit >45%) in 52 cases (4.6%). The obtained results demonstrate the practical interest of the subject, although additional studies are required in order to validate our approach to the clinical significance of this hematocrit-dependent interference in the Tacrolimus MEIA.
authors.affiliation: Laboratorio Central, Hospital Clínico Universitario, Santiago de Compostela, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Hermida
authors.forename: M Concepción
authors.initials: MC
authors.lastname: Fernández
authors.forename: J Carlos
authors.initials: JC
authors.lastname: Tutor
mesh_terms: D016477:Artifacts; D015510:Clinical Medicine / Q000379:methods*; D016903:Drug Monitoring / Q000379:methods*; D006400:Hematocrit; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D007166:Immunosuppressive Agents / Q000097:blood* / Q000627:therapeutic use; D016030:Kidney Transplantation; D016031:Liver Transplantation; D015203:Reproducibility of Results; D016559:Tacrolimus / Q000097:blood* / Q000627:therapeutic use
chemical_list: D007166:Immunosuppressive Agents; D016559:Tacrolimus