FIG. 2.

Lower limit of detection of CMV DNA in plasma. DNA was purified from 200-μl reference plasma samples containing 20, 10, 5, or 0 CMV particles; 35 molecules of IC DNA were coextracted. Extractions were done four times for the specimens containing 20 and 0 particles and six times for specimens containing 10 and 5 particles. One-fifth of the extracted DNA was subjected to PCR, and the amount of CMV amplimers (filled triangles) and IC amplimers (open squares) was determined by ECL and expressed in LU. The cutoff level is indicated with a broken line.