CMV antibody titers to the sum of the four individual tests and using a mixture format. Antibody titers to the sum of the 4 antigens in the first cohort (A), second cohort (B) or using a 4 antigen mixture format in the second cohort (C). Each symbol represents individual samples from CMV-negative and CMV-positive samples determined by ELISA. In the case of the first cohort, the sum of the titer values from the four individual tests and a cut-off value of 15,000, showed 100% sensitivity and 100% specificity. In the case of the second cohort, the LIPS tests from the sum of the 4 individual tests (B) or tested simultaneously as a mixture of four antigens (C) showed almost identical results; in each case, LIPS detected 6 samples that were ELSA negative. The solid horizontal lines indicate the GMT of the antibodies in each group and the vertical lines show the 95% confidence intervals.