FIG. 4.

Quantitative PCR. Reference plasma was supplemented with CMV particles to a concentration of 150,000 CMV copies/ml, serial threefold dilutions were made in the same plasma, and Q-PCR was done for this dilution series. (A) ECL signals (LU) obtained with the CMV DNA probe (open squares) and the IC DNA probe (filled squares). (B) Values of the CMV DNA/IC DNA ratios after background correction (R). (C) CMV loads (number of copies of CMV per milliliter of plasma) were calculated by amplifying R by a constant factor (1,050). Negative controls (reference plasma) were included; the calculated loads for these controls varied between 0 and −2 copies/ml. The correlation coefficient (r) and slope were obtained by least-squares linear regression analysis.