Serum amyloid A in the diagnosis of feline sepsis.

Systemic inflammatory response syndrome (SIRS) and sepsis can be challenging to diagnose in cats. Retrospectively, we investigated the diagnostic and prognostic potential of serum amyloid A (SAA), a major feline acute-phase protein (APP), in a population of critically ill cats with SIRS related to trauma or sepsis. A total of 56 SIRS cats (trauma n = 27; sepsis n = 29) were included and compared with healthy controls ( n = 18). SAA concentration was significantly increased in SIRS cats compared to controls, confirming its potential for the detection of systemic inflammation in this species. Significantly higher values of SAA were detected in cats belonging to the sepsis group; however, according to the results of the receiver operating characteristic curve analysis, the value of using SAA (>81 mg/L) to discriminate septic cats was only moderate (AUC = 0.76). Additionally, cats with sepsis had significantly higher serum bilirubin concentrations and toxic neutrophil changes compared to the trauma group. Overall, 38 of 56 cats were survivors; 18 of 56 were non-survivors, with 83% of the non-survivors (15 of 18) belonging to the sepsis group. Serum bilirubin concentration, but not SAA, was able to predict outcome. Prospective studies are needed to assess the potential of SAA in the diagnosis of feline sepsis and outcome prediction.