The questions we ask during every feline examination in our feline-only practice are “When was the last time your cat was tested for FELV/FIV?” and “What was the result?” It is necessary to know this status in order to optimize the care and management our patient’s health. The alphabet soup of feline disease can be confusing for the client. In this series of articles I will attempt to explain the reasons for testing. I will start with the two most common, life-threatening infectious diseases. I will explain certain terms as I go along in an attempt to make things clear.