Guide to Veterinary QUADAS for reviewing diagnostic test for bovine tuberculosis

a. What is meant by this item: Differences in demographic, husbandry and severity of disease features between populations may produce measures of diagnostic accuracy that vary considerably. The item refers more to the generalisability or external validity of the results than to the possibility that the study may produce biased results. Reported estimates of diagnostic accuracy may have limited applicability (generalisability) if the spectrum of tested animals is not similar to the animals in which the test will be used in practice. It is therefore important that diagnostic test evaluations include an appropriate spectrum of animals for the test under investigation and also that a clear description is provided of the population of animals actually included in the study.