Detection of cytomegalovirus antibody in stored blood products using latex agglutination

The detection of antibody to cytomegalovirus (CMV) in donor sera is one effective method for the prevention of posttransfusion CMV infection in seronegative recipients. A passive latex agglutination test (CMV Scan, Hynson, Wescott & Dunning, Baltimore, MD) has been shown to be an acceptable method of screening sera from the blood donor population. The procedure for this test, however, does not permit the testing of stored donor blood products. To evaluate the feasibility of testing blood components at various times during storage, the authors examined 25 CMV-positive and 25-CMV negative samples of CPDA-1 plasma from 50 units each of platelets and red cells. Plasma samples from platelets stored at 22 degrees C were tested on each of the 5 days of storage. Samples from red cell units stored at 2 to 6 degrees C were tested on storage Days 1, 2, 4, 6, 8, 10, 12, and 14. Of 250 tests done on plasma from platelet units, there were 123 true-positive and 123 true-negative results (sensitivity and specificity, 98.4%). Of 400 tests on plasma from red cell units, there were 200 true-positive and 198 true-negative results (sensitivity, 100%; specificity, 99.5%). These data show that the CMV Scan test can be used reliably to test segments of CPDA-1 plasma from platelets stored for up to 5 days and from red cells stored for up to 14 days.