FIP blood tests: A/G ratio, inflammation markers and CBC

A low A/G ratio is not a diagnosis

FIP may produce low albumin and increased globulins, lowering the albumin-to-globulin ratio. Other inflammatory, infectious and neoplastic diseases can do the same. In a referral population of 100 cats, low A/G cut-offs had limited positive predictive value, so the result was more useful as one part of a probability assessment than as a stand-alone confirmation.

Results considered together

• CBC findings such as anaemia, lymphocyte and platelet changes
• Albumin, globulin and bilirubin
• Inflammatory markers such as SAA or AGP where available
• Imaging and the presence or absence of effusion
• Clinical signs, weight and changes over time

Trends matter

During care, veterinarians compare clinical response and serial laboratory results rather than chasing one number. Contact the treating veterinarian if results stall or worsen; do not change a treatment plan from a laboratory value alone.