May 13, 2010
Johne's Antibody Assay
The serology section is now using Idexx's new Mycobacterium paratuberculosis (M. pt.) ELISA antibody test kit. This new assay can effectively evaluate M. pt. antibody levels in bovine serum, plasma, and milk. The ability to use milk or plasma as acceptable samples will be new features of this assay. Improved sensitivity and the ability to test milk samples are the major advantage of this assay.
The data below summarizes three separate studies conducted by Idexx using serum in study 1, plasma in study 2, and milk in study 3. The ELISA results in the study were compared to M. pt. culture results. Any of the three sample types tested showed improved sensitivity when compared current antibody assays. The 74.2% sensitivity when using milk as the test sample is very exciting. The assay while not approved for use in small ruminants in the United States is widely used in Europe for the screening of sheep and goat serum samples for antibodies to M. pt.
|Relative Sensitivity and Specificity
using characterized positive and negative samples
||serum vs cul.
||51.4% / 99.3%
||plasma vs cul.
||54.9% / 100%
||milk vs cul.
||74.2% / 99.8%