Infectious laryngotracheitis (commonly known as ILT) is a viral respiratory disease of chickens centred on the trachea. ILT can cause serious production losses due to a combination of mortality and depressed egg production. This disease can manifest itself in a variety of forms ranging from severe to mild with the latter being increasingly encountered in developed poultry industries and appearing as a mucoid tracheitis, sinusitis and conjunctivitis coupled to unthriftiness and low mortality. 

Infectious Laryngotracheitis Virus Antibody Test Kit is used for quantitative detection of antibodies against Infectious Laryngotracheitis virus (ILT) in chicken serum and yolk. 
Inactivated antigen is bound to a microwell. Diluted sera is added to the microwell and incubated. Any anti-ILT antibodies present in the serum will bind to the AIV on the microwell forming an AIV antigen-antibody complex. After washing away any unbound material, anti-Chicken IgG Alkaline Phosphatase conjugate is added to the microwell. The conjugate will bind to the ILT antigen-antibody complex. After incubation any unbound conjugate is removed by washing. Enzyme substrate is then added to the microwell. The substrate reacts with any Alkaline Phosphatase present and forms a yellow product. In the final step the reaction is stopped, fixing the color. The intensity of the color is measured photometrically at 405 - 410 nm with a 630-650 nm reference filter.