How we evaluate panagglutinating sera

P anagglutinating sera is one of the most challenging dilemmas of the antibody identification process. It occurs when patient sera react with all red blood cells (RBCs) tested, that is, with both screening and identification panel cells used in first approach. In this situation systematic workup is necessary to reduce the risk of error and optimize sample use. Two main problems must be resolved. The first is to determine whether panagglutination is due to an autoor alloantibody against a high-frequency antigen (HFA) or to multiple antibodies recognizing antigens other than HFA. The second problem is to detect the possible concomitant presence of clinically significant alloantibodies masked by panagglutination. The purpose of this article is to describe an algorithm developed to resolve these panagglutination problems at our laboratory that performs around 8000 RBC antibody identification tests each year for routine and reference purposes in the pretransfusional and obstetrical setting. Of a total of 52,000 antibody identifications performed over the past 7 years, the technique described here was used to investigate 3124 cases of panagglutination including 3002 associated with positive autocontrol tests and 122 with negative autocontrol tests (Table 1). To illustrate the problem-solving efficacy of this approach, we will present the results achieved at each step. Many of these results, particularly those involving HFA, were subsequently confirmed by a reference laboratory.