Tests are used by vets to help them diagnose disease in animals that are ill, which means your vet may ask you to bring in a 'urine sample' (water sample) from your pet to help him find out what's wrong with him. Urine samples are usually taken to check for diseases such as diabetes or cystitis. Urine samples are also often used as part of a routine health check to detect hidden disease before the development of obvious symptoms; this allows your pet to be treated earlier and more effectively.