Validation of a New Quick and High‐Throughput Latex Agglutination Immuno‐Assay for Feline Alpha‐1‐Acid Glycoprotein

BACKGROUND: Alpha-1-acid glycoprotein (AGP) is currently considered the most sensitive and specific inflammatory marker for diagnosing feline infectious peritonitis (FIP) and monitoring cats undergoing antiviral treatment. Various feline AGP assays have been validated, but currently, no assay compatible with biochemistry analyzers is available for the rapid analysis of high sample volumes in reference laboratories. OBJECTIVES: This study aimed to validate a novel method of AGP measurement in cats using a latex agglutination immunoassay on the Cobas 6000 (Roche, Meylan, France) and establish a reference interval (RI). METHODS: Surplus serum/heparin plasma sample pools with low (~330 μg/mL), medium (~970 μg/mL), and high (~2600 μg/mL) AGP concentrations, determined by the latex agglutination immunoassay, were used to establish intra- and inter-assay coefficient of variation (CV). Precision, linearity, recovery, and stability were assessed using pooled samples. RI was determined on surplus serum samples of 43 healthy cats. RESULTS: = 0.99) was observed for AGP concentrations between 194.1 and 1412.4 μg/mL. The upper reference limit was 622.8 μg/mL (90% confidence interval 517.1-713.7 μg/mL). Age and sex did not have a significant impact on AGP concentrations. CONCLUSIONS: The latex agglutination immunoassay allows a precise and high-throughput analysis of AGP concentrations in cats. This assay will greatly enhance the availability of AGP measurements.