Evaluation and comparison of serum procalcitonin and heparin-binding protein levels as biomarkers of bacterial infection in cats

Objectives: As bacterial infection can lead to sepsis and high mortality, early and easy diagnosis of sepsis can improve survival. In cats, the diagnosis of systemic bacterial infection is quite challenging, and, usually, non-specific markers for inflammation are employed. In humans, procalcitonin, heparin-binding protein and absolute neutrophil count are biomarkers that are studied in bacterial infections and sepsis owing to their high sensitivity and specificity. Methods: A total of 56 cats were categorised into 16 healthy cats and 40 bacterially infected cats, diagnosed by various examinations. In all cats, serum procalcitonin and heparin-binding protein levels were measured using ELISA and an absolute neutrophil count was performed. Results: The median values of procalcitonin levels and absolute neutrophil count were significantly higher in the infection group than in the normal group, but heparin-binding protein levels were not. A procalcitonin level >366 pg/ml was a better biomarker of bacterial infection than heparin-binding protein and absolute neutrophil count (sensitivity: 67.5%; specificity: 93.8%). Procalcitonin was not correlated with heparin-binding protein (r = 0.213, P = 0.115) and absolute neutrophil count (r = 0.393, P = 0.003). Conclusions and relevance: High procalcitonin levels in cats were associated with bacterial infection. Hence, procalcitonin could be a valuable marker for diagnosing bacterial infections in cats.