The viral testing can also be added onto other blood tests that your veterinarian is doing on your cat for wellness, or when your cat is sick. (dallasmetropaws.com)
Other blood tests such as rheumatoid factor are obtained to exclude rheumatoid arthritis. (thepsoriasisprogram.com)
As for any other maladies she likely has, the vet couldn't perform other blood tests because she just didn't have enough blood! (thearra.com)