A comparison of globulins, laboratory and refractometer measured total proteins as indirect tests to diagnosis failure of passive transfer in newborn calves

Abstract

In this study we compared globulin concentrations, total proteins measured in a laboratory, and total proteins measured with optical refractometer, to immunoglobulin G (IgG) concentrations measured by Enzyme-Linked Immunosorbent Assay (ELISA). Linear regression was used to determine their correlation coefficient (r): globulins r = 0.91, TPLab r = 0.87, and TP-Refractometer r = 0.78, their coefficient of determination (r2 ): globulins r 2 = 0.78, TP-Lab r 2 = 0.68, and TP-Refractometer r 2 = 0.51, and using the equation of the regression line the theoretical corresponding value of each of the above measurements was determined for a IgG concentration of 8 mg/ml and 10 mg/ml: globulins = <21.5 mg/ml and <23.5 mg/ml, respectively, TP-Lab = <43.5 mg/ml and <45.5 mg/ml, respectively, and TP-Refractometer = <46.5 mg/ml and 48 mg/ml, respectively. Globulins had very good correlation with IgG levels and preformed the best in this study, followed by TP-Lab, and then TP-Refractometer.