Data were managed and analyzed using Excel (Microsoft) and SPSS (ver. 15) software. For each extraction protocol, the presence and relative amount of rRT-PCR inhibitor(s) was determined by comparing MS2 rRT-PCR Ct results obtained in the absence or presence of stool suspensions. Measured MS2 Cts results were assigned to one of five levels of inhibition: no inhibition, inhibition of 1 to 3 Cts (2 to 8 fold), inhibition of 4 to 6 Cts (16 to 64 fold), inhibition of 7 to 9 Cts (128 to 512 fold) and inhibition of $10 Cts ($1024 fold). Similarly, the presence and relative amount of inhibitors of enterovirus RNA rRT-PCR was determined by comparing enterovirus rRT-PCR Ct results obtained in the absence or presence of stool suspensions for enterovirus added before extraction or enterovirus RNA added after extraction. The inhibition for suspensions that gave Cts for MS2 rRT-PCR below that for MS2 in suspension buffer alone was set to 0. The upper limit for rRT-PCR inhibition was capped at 29 Ct.