#129
THE USE OF ADSORB OUT FOR ANTIBODY IDENTIFICATION VIA FLOW BEAD IMMUNOASSAYS IN DIFFICULT PATIENTS.
Reva H. Goggins B.S. 1, Karen O'Keefe B.S. 1, Kris Wolfe M.S. 1, Marc I. Lorber M.D. 1 and Lisa A. Cuchara Ph.D. . 1 Histocompatibility & Immune Evaluation Lab, Yale. Univ. School of Medicine, New Haven, CT, USA .
We have been utilizing the LabScreen methodology for assessing PRA levels 
antibody (Ab) specificity for several years. As a result of Luminex
s increased sensitivity we are able to more accurately identify anti-HLA Abs and better assist our transplant team. As with any Ab screening method, not all patient sera are successfully assessed with this method. We occasionally come across pts with non-specific high background (bkgrd) that makes Ab assessment difficult (due to control values outside our acceptable range [very high neg ctrls or very low pos:Neg ctrls]. The object of this study was to determine if Adsorb Out could reduce non-specific high bkgrd in our problem sera without affecting normal bkgrd while still allowing the detection of 
true
anti-HLA Abs.
We tested 130 samples (69 normal 61 high bkgrd) with w/o Adsorb Out. 57% (35/61) of the high bkgrd samples converted to a normal bkgrd, while 26 still showed high bkgrd (43%). After Adsorb Out we were EVEN able to obtain a PRA result on 8 sera that were NOT obtainable w/o Adsorb Out. In 61 sera that converted from high to normal bkgrd we also looked at PRA levels (2 cI 3 cII changes were seen) and at the effect of Adsorb Out on antibody specificity, which for the most part stayed the same. In conclusion, treatment with Adsorb Out converted 57% of our high bkgrd samples into normal range bkgrd, and allowed for a PRA determination in some sera that would otherwise have been completely inconclusive. We will continue to use Adsorb Out for our monthly Ab screening on our patients that consistently demonstrate a high background when screened by the Labscreen/Luminex methodology.