Conceptual schematic representing the process of combining targeted sampling with baseline random sampling to substantiate freedom from disease. TS is the targeted sampling component, bsRS denotes the baseline stratified random sampling component with the sensitivity CSebsRS, cTS&bsRS is the combination of targeted and random sampling, OSe is the required overall sensitivity to demonstrate freedom from disease and X represents the sensitivity of the TS component, the value of which can be calculated using eq. (4).
Blickenstorfer et al. BMC Veterinary Research 2011 7:49 doi:10.1186/1746-6148-7-49