Performance characteristics of two automated solid-phase red cell adherence systems for pretransfusion antibody screening: a cautionary tale

Our institution has implemented two instruments, the Galileo and the Echo, that use different solid-phase red cell adherence assays for antibody screening in pretransfusion compatibility testing. During the initial implementation of these two instruments, we noticed very different problems: falsely positive results on the Galileo, and falsely negative results and lack of reproducibility on the Echo. Comparison of falsely positive antibody screen results from approximately equivalent numbers of samples run on the Galileo and samples tested by standard manual tube technique using low-ionic-strength saline enhancement showed a false-positive rate of 1.4 percent on the Galileo (defined as a positive screen with a negative panel). Testing using the Echo identified four cases of falsely negative antibody screens, (defined as a negative screen on a patient sample subsequently shown to be positive by the same method). In addition, we note a lack of reproducibility on the Echo, which emphasizes the importance of replicate testing during validation of automated antibody screening platforms. Immunohematology2012;28:137–9.