Factors influencing the performance of an interferon-y assay for diagnosis of tuberculosis in goats
Investigation article published in The Veterinary Journal
October 1st, 2011
The interferon-gamma (IFN-gamma) assay is an effective tool for the diagnosis of tuberculosis in goats. The objectives of this study were to evaluate factors that might affect assay performance: (1) 0.1%, 0.3% and 0.5% phenol in purified protein derivative (PPD, tuberculin); (2) dialysis of PPD; and (3) delaying antigenic stimulation of blood samples for 8, 16 and 24 h after collection. The assay was performed in duplicate with two cut-off points. Dialysis of PPD reduced test sensitivity, whereas the concentration of phenol did not significantly affect test outcome. Delaying antigenic stimulation of samples >8 h resulted in a reduction in test sensitivity, compromising the capacity of the assay to detect infected animals. Performing the assay in duplicate was unnecessary, which has implications for reducing assay costs. These findings will facilitate the effective application of the IFN-gamma assay as an ancillary test in tuberculosis eradication programmes in goats.
Bezos J., Alvarez J., de Juan L., Romero B., Rodriguez-Campos S., Castellanos E., Saez-Llorente JL., Mateos A., Dominguez L. and Aranaz A.
 | Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM). |
| Servicio de Micobacterias (MYC). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM). |
 | Instituto de Investigación en Recursos Cinegéticos (IREC). Consejo Superior de Investigaciones Científicas (CSIC). Universidad de Castilla La Mancha (UCLM). Gobierno de Castilla-La Mancha (JCCM). |
| Dirección General de Recursos Agrícolas y Ganaderos. | |
 | Ministerio de Medio Ambiente y Medio Rural y Marino (MARM). |
