AGP and SAA for FIP

Feline infectious peritonitis (FIP) is a challenging disease; it is difficult to diagnose and, until recently, was invariably fatal. COVID-19 identified the anti-viral compounds GS-441524 and Remdesivir, and studies have shown that they are safe¹and remarkably effective, resolving >85% of cats with FIP after 6² to 12 weeks of treatment³. Despite these advancements, diagnosing FIP remains challenging due to the lack of specific markers. Diagnosis typically involves a combination of physical examination, medical history, and laboratory testing, such as immunohistochemistry and reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Therefore, a comprehensive clinical and laboratory evaluation is necessary to rule out other potential causes of disease.

In recent years, acute phase proteins (APPs) such as α-1-acid glycoprotein (AGP), serum amyloid A (SAA) and haptoglobin (Hp) have been studied as potential biomarkers for FIP. AGP, in particular, has demonstrated higher diagnostic efficiency for FIP compared to other laboratory tests^4,5 making it a valuable tool for supporting FIP diagnosis. Additionally, AGP measurement is emerging as a parameter for monitoring therapeutic success, reflecting its growing clinical significance^6,7.

SAA is a major acute-phase protein in cats, increasing within hours of any inflammatory stimulus. It may be particularly useful for supporting the suspicion of a relapse in a cat previously diagnosed with FIP, as SAA levels are expected to rise before an increase in AGP is observed.

AGP and SAA analysis are now being offered by Easter Bush Pathology to help in aiding diagnosis, monitoring response to treatment and these proteins may be useful in confirming suspected relapse cases of FIP. AGP and SAA testing is £25 +VAT each. Testing on serum is recommended and a minimum of 0.5ml of serum is required; these tests can be added to our routine biochemistry panels or run separately. AGP testing can also be done on effusion (minimum volume 0.5 ml); however, if sending a body cavity effusion, it should be noted that these proteins are often lower than when observed in serum therefore serum and effusions cannot be used interchangeably for monitoring.