Investigation of C-Reactive Protein and Other Blood Inflammation Markers in Dogs

The Acute Phase Response (APR) causes the onset of modifications of some blood biochemical and leukocyte parameters. Objectives: Several canine inflammatory markers were investigated. C-reactive protein (CRP) concentrations were considered as elective marker of APR and compared to: i) concentrations of Fibrinogen (Fib), Albumin (Alb), and Iron (Fe); ii) counts of total Leukocyte (WBC), Segmented Neutrophils (NeuSeg), and Band Neutrophils (Band); iii) cytological estimation of Toxic Neutrophils (NeuTOX), Activated Monocytes (MonACT), and Reactive Lymphocytes (LymphREA). Methods: Based on retrospective investigation of CRP concentrations of a Veterinary Teaching Hospital database, two populations were selected: “inflammatory group” with CRP ≥0.30 mg/dL (#1080 samples) and “noninflammatory group” with CRP ≤0.29 mg/dL (#757). Data collected were analysed with MedCalc® software. Results: Dogs belonging to inflammatory group were significantly older (>7 years old) (P<0.05; Relative Risk, 1.38). Low yet significant correlations between CRP and other markers were noted (P<0.01) (Spearman Rank correlation): Fib, +0.26; NeuSeg, +0.26; WBC, +0.24; Alb, -0.21; Band, +0.14; Fe, -0.08; NeuTOX, +0.23; MonACT, +0.22. ROC analysis yielded the following AUC: NeuSeg, 0.71; WBC, 0.70; Fib, 0.67; Alb, 0.64; Fe, 0.64; Band, 0.59. Best combination of Sensitivity (SS) and Specificity (SP) was Fib (SS, 52.7; SP, 77.5 for 400 mg/dL cut-off) and Band (SS, 17.6; SP, 98.0 for 0.3 K/μL cut-off). Conclusions: The correlation between CRP and other parameters (except LymphREA), is significant but low. The diagnostic power of each inflammatory marker compared with CRP is low but combining more parameters simultaneously the accuracy of APR is increased.