An analysis of the performance characteristics of serological tests for the diagnosis of Neospora caninum infection in cattle.
OBJECTIVE
To analyse the performance characteristics (sensitivity/specificity) of two enzyme-linked immunosorbent assays (ELISA) against the indirect fluorescent antibody test (IFAT).


METHODS
A total of 1199 sera were tested in two ELISAs and the IFAT and results analysed utilising software that performed a receiver-operating characteristic (ROC) analysis.


RESULTS
Sensitivity and specificity for the two ELISAs were calculated for a range of different cut-offs. Minimal misclassification was achieved at cut-offs that, in the case of the Central Animal Health Laboratory (CAHL)-ELISA were in line with previously published cut-off values. In the case of the IDEXX-ELISA lower cut-off values than suggested by the manufacturer were calculated.


CONCLUSIONS
ROC-analysis resulted in optimised, as compared to the IFAT, cut-off thresholds for the CAHL and IDEXX-ELISA which can be further adjusted depending on the purpose of the investigation.
Novartis Animal Health Australasia Pty Ltd., Yarrandoo, 245 Western Road, NSW 2171, Kemps Creek, Australia. michael.reichel@ah.novartis.com
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Reichel
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Pfeiffer
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology; D003048:Coccidiosis / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D018688:Neospora / Q000302:isolation & purification*; D009520:New Zealand / Q000453:epidemiology; D012372:ROC Curve; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies