Open AccessComparison of diagnostic techniques for detection of Giardia duodenalis in dogs and cats
Author(s) -
Saleh Meriam N.,
Heptinstall Jack R.,
Johnson Eileen M.,
Ballweber Lora R.,
Lindsay David S.,
Werre Stephen,
Herbein Joel F.,
Zajac Anne M.
Publication year - 2019
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/jvim.15491
Subject(s) - feces , gold standard (test) , cats , medicine , giardia , diagnostic test , veterinary medicine , diagnostic accuracy , immunoassay , gastroenterology , biology , immunology , microbiology and biotechnology , antibody
Background An evaluation of currently available in‐clinic diagnostic tests for Giardia duodenalis infection of dogs and cats has not been performed. In addition, there is discordance among published diagnostic comparisons. The absence of a true gold standard for detecting Giardia duodenalis also complicates diagnostic evaluations. Objectives To evaluate diagnostic tests commercially available in the United States for detecting Giardia duodenalis in dogs and cats, in comparison to a widely used reference test, the direct immunofluorescent assay (IFA), and also to compare the results of 2 methods of analysis: comparison of diagnostic tests to a reference test (IFA) and Bayesian analysis. Animals Fecal samples from a convenience sample of 388 cats and dogs located in Colorado, Oklahoma, and Virginia. Methods Fecal samples were tested for Giardia duodenalis by zinc sulfate centrifugal fecal flotation and 4 different commercial diagnostic immunoassays. Results were analyzed via Bayesian analysis and by comparison to the IFA as the reference test. Results Sensitivity and specificity by comparison to IFA was ≥82% and ≥90%, respectively, for all diagnostic tests in dogs and cats. When analyzed via Bayesian analysis, sensitivity and specificity were ≥83% and ≥95%, respectively. When ZnSO 4 centrifugal fecal flotation results were combined with immunoassay results, there was no longer a significant difference between the sensitivities of the commercial in‐clinic immunoassays. Conclusion and Clinical Relevance The Bayesian analysis validates using IFA as the reference test. Differences in commercial in‐clinic immunoassay sensitivities can be mitigated when the results are combined with ZnSO 4 centrifugal fecal flotation results.