Polyagglutination in hospitalized patients: a prospective study.

A hospital population at high risk for red cell polyagglutination was studied prospectively in search for cryptantigen exposure. The patients included in this study suffered from: malignancies, sepsis, direct antiglobulin test (DAT) negative anemias and various combinations of these three. 238 patients were examined, and 18 of these (7.6%) were found to have exposed cryptantigens on their erythrocytes. This is an unexpectedly high percentage. Our findings suggest that cryptantigen exposure on the red cells is a more common phenomenon than previously described, especially when looked for in a carefully chosen population. The red cells of these patients are potentially polyagglutinable, and screening with lectins will ensure their pretransfusion identification and evaluation.