P085 : RAPID METHOD TO ELIMINATE HIGH BACKGROUND ON LUMINEX-SINGLE ANTIGEN BEADS (L-SAB) IN SERA FROM PATIENTS WITH VENTRICULAR ASSIST DEVICES (VAD)

Aim Antibody to albumin (Alb-Ab) can develop in VAD patients and causes high background on L-SAB. The aim of the study was to eliminate the non-specific signals by BSA coated bead (BK-Bead) absorption. Methods BK-Bead absorption: Sera with high background on L-SAB (One Lambda, Inc.) were absorbed twice by mixing BK-Beads with serum at 1:10 ratio and vortexing for 10 min at RT each time. Absorbed sera were then retested by L-SAB per manufacturer’s protocol. Results Alb-Ab developed 15–30 days after VAD implantation and significantly decreased within 1–3 months after transplantation in all VAD patients ( Fig. 1 ). A total of 77 samples from 29 patients were tested by L-SAB before and after BK absorption. BK absorption successfully eliminated the Alb-Ab high background on #1 NC bead as well as HLA-Ag specific beads in all VAD samples with high background ( Fig. 2 ). BK-Bead absorption has no effect on the detection of true HLA-Ab in non-VAD samples ( Fig. 3) . Conclusion This simple and rapid BK-Bead absorption procedure can efficiently remove Alb-Ab from VAD patient samples and eliminate its non-specific signals without affecting the detection of true HLA-Abs on L-SAB.