Fig. 3

Comparability of results of various PCR methods in use by six laboratories (Lab 1 to Lab 6) on bronchoalveolar lavage fluid (BALF) samples (n = 21) from veal calves from farms with bovine respiratory disease (BRD). BALF samples were tested twice by the PCR methods and the mean Ct values were calculated from the real-time PCRs. Viability of M. bovis in the BALF samples was verified with culture. On the basis of the culture results, the figure was split in two parts, either with BALF samples negative or positive for M. bovis by culture. Raw data to this figure are provided in Additional file 1