Comparison of the performance of microtube column systems and solid-phase systems and the tube low-ionic-strength solution additive indirect antiglobulin test in the detection of red cell alloantibodies.

To compare the performance of seven currently available test systems in the detection of erythrocyte alloantibodies (ab), we tested in parallel 446 sera samples containing red cell ab [368 sera samples with ab that are assumed to be clinically significant (cs-ab) and 78 sera samples with ab that are assumed to be of minor clinical significance (ms-ab)] using the tube spin low-ionic-strength solution (addition method) indirect antiglobulin test (tube LISS-IAT), three microtube column agglutination techniques (DiaMed-ID, Ortho BioVue and Bio-Rad Scangel), one affinity adherence test system (CLB/Mast CellBind Screen) and two solid-phase tests [Biotest Solidscreen II and Immucor Capture-R Ready-Screen (4)]. To address the specificity of the three test systems under routine conditions, results of 4566 patient samples obtained using the tube LISS-IAT, results of 5205 patient samples obtained using the Scangel and results of 3560 samples obtained using the Capture-R were evaluated. The DiaMed-ID detected 344 cs-ab and 43 ms-ab, BioVue 333 cs-ab and 48 ms-ab, Scangel 348 cs-ab and 62 ms-ab, CellBind Screen 346 cs-ab and 47 ms-ab, Solidscreen 330 cs-ab and 38 ms-ab, Capture-R 358 cs-ab and 45 ms-ab and LISS-IAT 159 cs-ab and 12 ms-ab. In routine practice, erythrocyte cs-ab could be identified in 61 (67.8%) of 90 reactive sera (specificity: 98.6%) in the tube LISS-IAT, in 169 (58.7%) of 288 (94.4%) in Bio-Rad Scangel and in 101 (51.0%) of 198 reactive sera (94.3%) in Capture-R. We conclude that the sensitivity of the microcolumn, affinity adherence and solid-phase test systems in the detection of cs-ab was similar and was markedly superior to that of the conventional tube LISS-IAT. All high-sensitive test systems produced higher rates of false positives and ms-ab compared to the tube test. An individual cost-benefit analysis, considering the recent knowledge about the clinical significance of weak-reactive cs-ab, should be performed in every institution to decide whether and if so which high-sensitive screening system should be applied.