In the field of veterinary medicine, hematological indices such as the neutrophil-to-lymphocyte (NLR), monocyte-to-lymphocyte (MLR), platelet-to-lymphocyte (PLR), systemic immune–inflammatory index (SII), aggregate systemic inflammation index (AISI), and systemic inflammatory response index (SIRI) are increasingly recognized as cost-effective indicators of systemic inflammatory activity. Despite their diagnostic potential, standardized reference intervals for these metrics remain undefined in clinically healthy feline subjects. Consequently, the primary objective of this investigation was to establish baseline reference ranges for these inflammatory ratios in cats, thereby facilitating more accurate clinical interpretations and diagnostic assessments in feline practice. Clinical records were reviewed retrospectively, and cats showing no abnormalities on physical examination and presenting laboratory values within established reference ranges were included in the analysis. Following the sex-based analysis of 88 samples, the reference intervals were defined as follows: 0.8–7.1 for NLR; 0.1–0.6 for MLR; 22.7–374.6 for PLR, 130–2454 for SII, 39.5–1542.8 for AISI, and 0.2–6.1 for SIRI. Comparison by sex did not demonstrate statistically significant differences in any of the analyzed indices. These findings may offer a significant clinical framework for the interpretation of hematological inflammatory markers in feline patients.
Ertürk et al. (Sun,) studied this question.