Comparison of Maxwell 16-S, Maxwell 16-M and QIAamp method for extraction of influenza virus RNA from pooled fecal samplesa.

aThe CDC Flu A Real-time RT–PCR assay was performed after RNA extraction from fecal pools with the three extraction protocols. Since a known amount of virus was added to all the fecal samples except for ten naturally infected samples, no internal positive control was introduced into the PCR assay. Each pooled fecal sample (10%, W/V) consisted of feces from three individuals of the same type. A Ct value of 45 was used to represent a negative sample result. IQR, interquartile range. CtS−Q is Maxwell 16-S minus QIAamp. CtM−S is Maxwell 16-M minus Maxwell 16-S.*P