Agarose gel showing amplification of BK and JC viral DNA with BK-specific and JC-specific primers. Lane 1 is the φx174 DNA/HaeIII marker. Lanes 2 to 8 show results with BK-specific primers. Lane 2, no template; lanes 3 to 5, BK stock virus template at 1:1, 1:10, and 1:100 dilutions; lanes 6 to 8, JC stock virus template at 1:1, 1:10, and 1:100 dilutions. Lanes 9 to 15 show results with JC-specific primers. Lane 9, no template; lanes 10 to 12, BK stock virus template at 1:1, 1:10, and 1:100 dilutions; lanes 13 to 15, JC stock virus template at 1:1, 1:10, and 1:100 dilutions.