P008 Case scenario, performance differences of the two commercially available solid phase single antigen reagents

Abstract

Aim Luminex single antigen technology for antibody identification has enabled laboratories to provide highly accurate virtual crossmatch results prior to transplantation. Both manufacturers, One Lambda (OL) and Immucor (IC) single antigen reagent panels differ in the HLA alleles composite and density. We report here two cases that single antigen panel for each behave significantly different. Method Serum of Patient (RH) and (AM) were tested with OL and IC single antigen panels. Flow cytometry and CDC crossmatchs of both patients were performed with their corresponding donors. Results Serum of (RH) and (AM) tested with OL single antigen panel that showed the following DSA’s, anti DQB1*06:03 (2510 MFI) and anti A2 (891 MFI), B41 (1631 MFI) respectively. CDC and flow crossmatch were highly positive for both sera despite low Median Fluorescent Intensity (MFI) of the identified DSA. The same sera were tested with IC single antigen panel; patients (RH) and (AM) showed anti DQB1*06:03 (17946 MFI) and anti A2 (10500 MFI) respectively. Furthermore, both sera were diluted 1:4 and re-tested with OL single antigen panel. The identified DSA strength in the diluted sera for both patients showed higher MFI values for A2 (3048 MFI), B41 (2863 MFI) for AM patient and DQB1*06:03 (10503 MFI) for RH. Conclusion Significantly, higher prozone effect was observed with OL single antigen panel than in IC. Serum to bead-volume ratio may have contributed to the lower correlation between OL versus IC. Testing patients sera by more than one manufacturer is an advantageous in determination of antibody strength and improves correlation with the crossmatch results.