title: Inter and intra laboratory concordance of HLA antibody results obtained by single antigen bead based assay.
abstract: Single antigen bead based assays (SAB) to identify antibodies to HLA are marketed as a qualitative test, however often used as a quantitative test as the results provide mean fluorescence intensity (MFI) which is found to correlate with the strength/avidity of the antibody. We studied the between and within laboratory variability in performing the SAB from one manufacturer. Ten samples were tested at four laboratories according to the manufacturer's suggested protocol. Additionally same samples were tested on four consecutive days in one laboratory. All tests were performed using the same lot of beads and secondary antibody. Results were classified as positive at four different MFI cutoffs: 1000, 5000, 8000 and 10,000. MFI values across and within the laboratory were compared in a pair-wise fashion with Pearson's correlations. Overall concordance for Class-I was 97% between laboratories and 98% within laboratory at all cutoffs. Pair-wise Pearson correlation between laboratories was 0.989-0.99, while within laboratory it was 0.998-0.999. For Class-II, overall concordance between and within laboratory was 98%. Pair-wise Pearson correlation between laboratories was 0.991-0.997, while within laboratory it was 0.997-0.999. There is good correlation between laboratories and within laboratory using the same manufacturer, same lot and same protocol while performing SAB.
authors.affiliation: Division of Transfusion Medicine, Mayo Clinic, Rochester, MN 55905, USA. Gandhi.manish@mayo.edu
authors.forename: Manish J
authors.initials: MJ
authors.lastname: Gandhi
authors.forename: Steven
authors.initials: S
authors.lastname: Degoey
authors.forename: Deborah
authors.initials: D
authors.lastname: Falbo
authors.forename: Sarah
authors.initials: S
authors.lastname: Jenkins
authors.forename: James R
authors.initials: JR
authors.lastname: Stubbs
authors.forename: Harriet
authors.initials: H
authors.lastname: Noreen
authors.forename: David F
authors.initials: DF
authors.lastname: Lorentzen
authors.forename: Jarhow
authors.initials: J
authors.lastname: Lee
authors.forename: Mark
authors.initials: M
authors.lastname: Stegall
mesh_terms: D000906:Antibodies / Q000097:blood / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology; D006680:HLA Antigens / Q000276:immunology*; D006650:Histocompatibility Testing / Q000379:methods / Q000592:standards; D006801:Humans; D007158:Immunologic Techniques / Q000379:methods / Q000592:standards*; D007753:Laboratories / Q000592:standards*; D008863:Microspheres; D015203:Reproducibility of Results
chemical_list: D000906:Antibodies; D006680:HLA Antigens