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The process of solid organ transplantations is implicated by two immunological barriers; ABO and HLA system. Recently, crossing ABO histo-blood group barriers becomes a common practise with the help of pre and post-conditioning protocols. The pre and the post-conditioning protocols are mainlyguided by the level of isohaemagglutinin i.e. anti-A and anti-B titres. In heart and lung transplantation additional dilutional effect in isohaemagglutinin level may be caused by thepriming solutions during Cardiopulmonary bypass (CPB). Measuring anti-A and anti-B titres before, during and after ABO incompatible organ transplantation and keeping them within defined value is crucial for positive outcome.Significant variations in titre reading have been observed between institutions. These variations are most likely to be associated with laboratory methodology in place. Therefore standardization of laboratory analyses has always been regarded as essential for insuring uniformity of results and for wide application of guidelines. Since antibody’ reactivity strength is approached semi quantitatively through testing of serial doubling dilution, standardization of such testing represent a solid challenges. Methods Eighteen CPB patients were enrolled in this study after being formally consented in pre-admission clinic at RMH. Samples were then collected before commencement of CPB and then in defined time points during the surgery and post-operatively. The baseline titres were evaluated with three methods (Tube, DiaMed and Ortho BioVue) and the rest of the samples were assessed with Ortho BioVue only. Samples from ABO-incompatible renal transplantation program at RMH along with samples from CPB study were used in the comparisons studies; A1 vs A2, anti-A and anti-B in group O individuals and in group B and A, testing at RT vs 37 oC vs IAT and finally Tube vs DiaMed vs Ortho methods. Results All patients showed a fall in titre during CPB. The average fall in titre was 1.22 steps with 14 patients showed a drop of 1 step and 4 patients showed a drop of 2 steps. The fall in titre almost took place during the first 30 minutes of CPB commencement. In comparison studies we found that A2 cells showed 3.5 steps lower in titre level when compared to A1 cells. We also showed the titre of anti-A and anti-B in group O individuals to be 2.2 and 1.5 steps higher respectively in IAT phase compared to that of RT and 37 0C phases. Anti-A was noted to be 1.7 steps higher than anti-B in group O individuals. In the other hand, anti-A and anti-B in group B and A individuals showed no significant difference in titre reading over the three phases. In methods comparison study, we concluded that titre reading would be of similar value between the three methods i.e. conventional tube test, DiaMed and Ortho BioVue(1) when the cut off read as +1(5) in Tube, +1(5) in Ortho and -/+(3) in DiaMed methods.
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