Determination of optimal method for antibody identification in a reference laboratory

Methods commonly used for antibody identification are hemagglutination (tube), column agglutination (gel), and solid-phase red cell adherence. Our AABB immunohematology reference laboratory (IRL) conducted a study to determine which antibody identification testing method was optimal for detecting all clinically significant antibodies. Patient specimens were sent to our IRL from August 2008 to September 2009. Routine testing was performed by tube method and then by manual gel and manual solid-phase methods. Of the 254 samples tested, 115 showed agreement in antibody identification with all three methods. The tube method identified all but six clinically significant antibodies. The gel method did not identify 59 clinically significant antibodies. Fifty-six clinically significant antibodies were not identified by solid-phase testing. Tube testing identified 27 clinically insignificant antibodies, primarily cold autoantibodies. Gel and solid-phase methodologies identified two and three cold autoantibodies, respectively. Solid-phase testing failed to detect 12 examples of anti-K. No identifiable pattern of reactivity was found in 13 samples using gel testing compared with 6 for solid-phase and none for tube methodologies. Hemagglutination tube method was the best choice for our IRL because it missed the fewest number of clinically significant alloantibodies. Benefits also included the ability to use various potentiating factors, incubation times, and temperature phases to enhance antibody identification. The tube method provided critical data for determining antibody clinical significance. Immunohematology2011;27:146–150.