Inputs


This utility estimates the probability of detecting disease
(herdsensitivity) in a
large (infinite) population, if it is present at the specified
design prevalence,
assuming a test of
known sensitivity and
specificity and that all samples have a negative test result. These analyses use the method from
Martin et el. (1992) (Prev Vet Med, 14:3343), assuming known test sensitivity and
test specificity and a cutpoint number of reactors of 1 to declare
a population infected (i.e. to be recognised as free there must be zero positive reactors).
See also Richards, MS (1983). Proceedings of the 3rd International Symposium on Veterinary Epidemiology and Economics, pp 567570.
Inputs are the sample size tested, test sensitivity, test specificity,
and the design (target) prevalence.
Outputs are:
 the herdlevel sensitivity and specificity for the given sample size, test sensitivity, test specificity and design prevalence; and
 a table and graph of herdsensitivity values for a range of design prevalence
and sample size values and herdspecificity for the same range of sample sizes.
