PCR, culture, serology – what’s the difference?

Polymerase chain reaction (PCR), bacterial or viral culture and serology are common methods used in veterinary diagnostics. The major application of these techniques in horses is in supporting the diagnosis of infectious diseases. However, different testing options are often available for the same disease. Which test should be used? This session will briefly discuss the overall principle of PCR, culture and serology and their diagnostic outcomes. Two diseases will be presented in more detail to illustrate how specific testing methods can support the diagnosis of each disease. One will be an infectious disease that is typically diagnosed on the pathogen-level by PCR (equine herpesvirus-1). The other disease (Lyme disease) is diagnosed by serological testing that determines the horse’s antibody response to the pathogen. The goal is to obtain an overall better understanding on test outcomes, what PCR, culture or serology results tell us, and which test(s) should be used when.