Herd Sensitivity/Specificity Calculator

Please ensure the sum of test sensitivity and specificity is at least than 100%

Please ensure the number of positve animals is less than the number sampled.


This calculator provides the user with the herd sensitivity and specificity based on a number of animals sampled and how many positive animals are required before we consider the herd is positive. It requires knowledge of the individual animal test sensitivity and specificity, herd size and the minimum within herd (or animal level) prevalence for a truly positive herd.

External References

Cameron A.R, & Baldock, F. C., Prev Vet Med, 1998 'A new probability formula for surveys to substantiate freedom from disease.', 34: 1-17



The calculated herd sensitivity and specificity are the lowest levels that can be achieved based on the inputs, particularly on the number of positive animals at which the herd should be considered positive.