Serum total sialic acid in pigs: new possibilities for an old inflammatory biomarker

The potential use of total sialic acid (TSA) as an acute-phase biomarker in pigs was investigated through clinical and analytic validation of an automated commercial enzymatic-colorimetric assay. Intra- and interassay precision, accuracy, and detection limit were determined for the analytical validation of the method. The intra- and interassay coefficients of variation (%CV) were 2.27% and 3.99%, respectively, whereas the linearity under dilution calculation resulted in a coefficients of correlation of r = 0.995 and r = 0.999 for TSA high- and low-content serum samples, respectively, which indicated that the automated method was reliable to measure TSA in porcine serum samples. Average serum TSA concentrations in diseased pigs (median: 1779.16 mg/l; 5th percentile: 556.62 mg/l; 95th percentile: 963.06 mg/l) were 2.5-fold higher compared with healthy animals (median: 692.78 mg/l; 5th percentile: 1278.74 mg/l; 95th percentile: 2536.12 mg/l), which indicated that TSA can be considered as a moderate acute phase marker in swine. Therefore, TSA may be useful for detecting inflammatory conditions and could be included in biochemical profiles used to monitor the general status of pigs as a moderate acute phase marker.