Utility of Serum Amyloid A-to-Albumin Ratio in Hospitalized Cats.

To evaluate a point-of-care (POC) feline serum amyloid A (fSAA) assay and to describe how fSAA and the fSAA-to-albumin ratio (SAR) in hospitalized cats correspond with outcome, illness severity, and presence of inflammation or infection. Prospective observational study. University teaching hospital. The POC fSAA assay was compared with a reference method in 51 cats. The POC fSAA and SAR were evaluated in 34 hospitalized cats. None. The POC fSAA and fSAA measured by reference laboratory methods were correlated (r = 0.72, p ≤ 0.001). For all cats, the median POC fSAA was increased (38.9 mg/L; range: 5.0-200.0 mg/L). The median POC fSAA for cats with positive outcomes (44.2 mg/L; range: 5-200 mg/L) was not different from cats with negative outcomes (23.6 mg/L; range: 5-91.0 mg/L) (p = 0.43). Most cats (28/34 [82.4%]) had increased SAR (median: 1270; range: 120-9010). The median SAR for cats with positive outcomes (1315; range: 120-9010) was not different from cats with negative outcomes (795; range: 130-6650) (p = 0.84). Cats with infection were more likely to have severely increased SAR (defined as >3 times the reference interval) (p < 0.004). Most cats with systemic inflammatory response syndrome (SIRS) had severely increased SAR (12/13 [92.3%]) compared with cats without SIRS (10/21 [42.8%]) (p = 0.008). The mean Acute Patient Physiologic and Laboratory Evaluation score of cats with positive outcomes (40.5 [±8.8]) was lower than in cats with negative outcomes (47.6 [±13.7]) (p = 0.015). There was agreement between the reference method and the POC fSAA assay. The SAR was increased in cats with infection and SIRS and did not correlate with outcome. fSAA and SAR may be useful in clinical applications and for the detection of infectious and inflammatory diseases in cats.