The development of a double-well ELISA test for the detection of turkey rhinotracheitis (TRT) virus antibody in turkey and chicken sera, utilising a streptavidin-biotin detection protocol is described. This test was compared with a conventional ELISA, which detects antibody using a peroxidase-labelled anti-turkey IgG. The double-well streptavidin-biotin ELISA was more sensitive than the conventional ELISA, and, due to the consistently low background values obtained, was further modified to a single-well ELISA test. Antibody titres obtained using the single-well streptavidin-biotin ELISA were similar to those obtained using the conventional ELISA. A microtitre serum neutralisation test for TRT virus read using an indirect immunoperoxidase (IIP) detection protocol after 48 h was also developed and compared to the standard neutralisation test employing a 7 day incubation and read by CPE. The specificity of the single-well streptavidin-biotin ELISA was confirmed using the rapid (IIP) serum neutralisation test.