24/09/2026
-Rivalta Test as a Diagnostic Aid for Effusive FIP-
👉The Rivalta test is a simple and rapid point-of-care test used to evaluate protein-rich inflammatory effusions in cats with suspected effusive feline infectious peritonitis (wet FIP).
👉A positive Rivalta test is characterized by persistence or precipitation of the effusion drop in the acidic solution, sometimes producing a characteristic jellyfish-like appearance. This finding supports the presence of a protein-rich inflammatory effusion but is not specific or confirmatory for FIP.
👉Therefore, Rivalta results should always be interpreted alongside other diagnostic findings, including hematology, serum biochemistry, albumin-to-globulin (A:G) ratio, total protein and cytology of the effusion, as well as more specific FCoV/FIP-associated testing when indicated. Integrating clinical signs, imaging, and laboratory findings provides stronger evidence to establish the diagnostic direction toward effusive FIP and to exclude other causes of inflammatory effusion.