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Title: Determination of the optimal cutoff value for a serological assay: an example using the Johne's Absorbed EIA.
Title Abreviation: J Clin Microbiol Date of Pub: 1993 May
Author: Ridge SE; Vizard AL;
Issue/Part/Supplement: 5 Volume Issue: 31 Pagination: 1256-61
MESH Headings: Animal; Antibodies, Bacterial (BL); Cattle; Cattle Diseases (*DI/IM); Decision Trees; Diagnostic Errors; Enzyme-Linked Immunosorbent Assay (*MT/SN); Evaluation Studies; Mycobacterium (IM); Paratuberculosis (*DI/IM); -RN-;
Journal Title Code: HSH Publication Type: JOURNAL ARTICLE
Date of Entry: 930629NEntry Month: 9309
Country: UNITED STATES Index Priority: 2
Language: Eng Unique Identifier: 93273937
Unique Identifier: 93273937 ISSN: 0095-1137
Abstract: Traditionally, in order to improve diagnostic accuracy, existing tests have been replaced with newly developed diagnostic tests with superior sensitivity and specificity. However, it is possible to improve existing tests by altering the cutoff value chosen to distinguish infected individuals from uninfected individuals. This paper uses data obtained from an investigation of the operating characteristics of the Johne's Absorbed EIA to demonstrate a method of determining a preferred cutoff value from several potentially useful cutoff settings. A method of determining the financial gain from using the preferred rather than the current cutoff value and a decision analysis method to assist in determining the optimal cutoff value when critical population parameters are not known with certainty are demonstrated. The results of this study indicate that the currently recommended cutoff value for the Johne's Absorbed EIA is only close to optimal when the disease prevalence is very low and false-positive test results are deemed to be very costly. In other situations, there were considerable financial advantages to using cutoff values calculated to maximize the benefit of testing. It is probable that the current cutoff values for other diagnostic tests may not be the most appropriate for every testing situation. This paper offers methods for identifying the cutoff value that maximizes the benefit of medical and veterinary diagnostic tests.
Abstract By: Author
Address: Victorian Institute of Animal Science, Department of Agriculture, Attwood, Australia.