This presentation will review the published reports of sensitivity and specificity of the CSL and IDEXX ELISA test for paratuberculosis in cattle. Additional ELISA and faecal culture data from twenty dairy herds where both faecal cultures and ELISA testing was done concurrently will be included. A cohort of 954 cattle cultured every six months from ten herds followed over four years will serve as the basis to ascertain the sensitivity of faecal culture to detect infected cattle in dairy herds. The cohort of 954 cattle included a cohort of adult (lactating) cattle of 697 cattle which were also sampled over the same four period at six month intervals. The sensitivity of faecal culture was based on state of the art culture techniques including centrifugation and double incubation. Of the 954 cattle cohort of all ages (calf to adult) that were faecal samples on the first herd visit, 79 were culture positive. An additional 131 animals were detected as culture positive over the next 3 1/2 years, when cultured at six month intervals. The sensitivity of faecal culture to detect infected cattle on the first sampling was 38%. With the 697 adult cattle cohort, 67 were positive on the first faecal culture, while an additional 91 were culture positive over the next 3 1/2 years, giving a sensitivity of detection at first culture of 42%. In neither case does this consider the animals culled from the herds prior to being detected, nor does it include the animals always culture negative but that will have culture positive tissues at slaughter. Both of these considerations will lower the apparent sensitivity of faecal culture.