Mean Ct values derived from real time RT-PCR analyses of nucleic acid extracts prepared by different extraction methods using the blood, stool and sputum test panels.

Shaded and non-shaded rows represent spiked (positive) and non-spiked (negative) samples, respectively; A–F represent coded identifiers of the six developers; the CDC used the Roche MagNaPure platform; PATH used the Qiagen extraction kits except for MTB; SP, sputum; BL, blood; ST, stool; ND no amplification detected; a 1–2 false negative RT-PCR replicate(s) detected within a confirmed positive member; b false positive RT-PCR replicate(s) detected within negative sample; Sens, mean sensitivity across all nine replicates; Spec, mean specificity across all nine replicates; CI, confidence interval. Dark shading indicates spiked samples; NC, not calculated.