title: Clinical efficacy of the Abbott Tacrolimus II assay for the IMx.
abstract: Monitoring tacrolimus is essential to maintain therapeutic concentrations. Performance of the new Abbott Tacrolimus assay (FK II) was evaluated and compared to the original tacrolimus assay (FK I). 189 trough whole blood samples from transplant cases were included in the study. Samples (n = 117) with FK I concentrations > 5 ng/mL were reanalyzed with the FK II assay. Patient samples (n = 43) that had FK I concentration < 5 ng/mL with apparent mean and range of 3.1 ng/mL and 0.7 to 4.5 ng/mL, respectively, were also reanalyzed with FK II to yield a mean of 5.9 ng/mL with a range of 2.9 to 10.8 ng/mL. Checking for patient compliance, samples (n = 10) with a FK I concentration of 0 ng/mL were re-analyzed. With one exception of a mislabeled cyclosporine sample, all samples (n = 9) showed FK506 levels greater than 2 ng/mL with the FK II assay. The FK II assay was shown to be a clinically efficacious assay, with improved sensitivity and acceptable precision versus the previous FK I assay.
authors.affiliation: Department of Pathology, Medical College of Wisconsin, Milwaukee 53226, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Cannon
authors.forename: S H
authors.initials: SH
authors.lastname: Wong
authors.forename: S
authors.initials: S
authors.lastname: Hariharan
authors.forename: M B
authors.initials: MB
authors.lastname: Adams
authors.forename: C P
authors.initials: CP
authors.lastname: Johnson
authors.forename: A M
authors.initials: AM
authors.lastname: Roza
authors.forename: M L
authors.initials: ML
authors.lastname: Pearson
authors.forename: C L
authors.initials: CL
authors.lastname: Werner
mesh_terms: D000328:Adult; D001741:Black or African American; D016903:Drug Monitoring; D005260:Female; D006084:Graft Rejection / Q000097:blood / Q000517:prevention & control*; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D016559:Tacrolimus / Q000097:blood*; D044465:White People
chemical_list: D007166:Immunosuppressive Agents; D011933:Reagent Kits, Diagnostic; D016559:Tacrolimus