<p>The plasma total protein is often analysed in clinical laboratories using biuret reagents in spectrophotometers, colorimeters, or chemistry analysers. Though the refractometric measurement of total proteins is faster and less expensive, its accuracy has not been determined in pigs. This study aims to investigate the accuracy of the total protein values obtained by refractometry and their use as a diagnostic monitoring tool in pigs. The objectives of this study were to [1] compare the plasma total protein concentrations in pigs measured by the refractometry and colorimetry (biuret) methods, [2] to determine if the refractometer provides reliable measurements of plasma total proteins [3] to compare the plasma total proteins values of anaemic pigs obtained by refractometry and colorimetry methods. EDTA blood samples were obtained from the jugular outflow of 130 pigs. Standard procedures were followed in all the haematological and plasma chemistry determinations. The total protein value obtained by refractometry was significantly (<i>P</i> &lt; 0.05) higher than that obtained by the biuret method. The Concordance Correlation Coefficient (CCC) analysis yielded a precision of 96.49%, indicating a strong linear association between the two methods, as confirmed by the Pearson correlation coefficient. The statistical accuracy was 96.65%, demonstrating that both methods are approximately 96% accurate for application in pigs. The CCC value obtained was 0.9326, indicating a moderate level of agreement between the methods. Furthermore, the Bland–Altman plot analysis identified an analytical and user error of 3.4%, which was deemed clinically insignificant. In anaemic pig samples, the plasma total protein concentrations obtained by the biuret method were significantly (<i>p</i> = 0.000) lower than those obtained by refractometry. The refractometer was sufficiently accurate for determining plasma total protein concentrations in both healthy and anaemic pig samples.</p>