Comparison of a Point-of-Care Glucometer (POCG) and an Automated Biochemical Analyzer to Measure Glucose Concentrations in Whole Blood, Serum, and Plasma from Porcine Blood Samples.

Accurate measurement of circulating glucose concentrations is critical when evaluating the metabolic status of swine. Point-of-care glucometers (POCGs) represent an expedient method for measuring glucose concentrations in whole blood samples given the insignificant blood volume required and the rapid results, but often this technology yields less reliable estimates of blood glucose concentrations compared to biochemical analyzers utilized in clinical diagnostic laboratories, likely due to a confounding effect of packed cell volume on POCG readings. Our objective was to test this hypothesis by determining the correlation between glucose concentrations measured by a POCG in serum, plasma, and whole blood compared to values measured in plasma by a biochemical analyzer. To accomplish this blood samples were collected via jugular venipuncture from 152 grow-finish Yorkshire swine during the postprandial state. Glucose concentrations were measured in whole blood, serum and plasma (in the presence and absence of the glycolytic inhibitor, fluorine) by a POCG and in fluorinated plasma using a biochemical analyzer. Resulting values were compared using Correlation and Bland-Altman analyses to determine if sampling methods were interchangeable. Glucose concentrations in whole blood as measured by a POCG were highly variable and poorly correlated with plasma glucose concentration measured by a biochemical analyzer (r²=.34). However, glucose concentrations in serum and plasma measured by a POCG were more strongly correlated with the plasma glucose concentration measured by a biochemical analyzer (serum, r²=.57; plasma, r²=.64 respectively). Plasma glucose concentration measured by a POCG in the presence of fluorine correlated the strongest with plasma glucose concentration measured by a biochemical analyzer (r²=.89). Bland-Altman analysis revealed the mean differences in glucose concentrations determined by biochemical analyzer and by POCG in whole blood, serum, plasma, and fluorinated plasma were 43.5, 33.5, 12.4, and 4.5 mg/dl, respectively. These results indicate that the use of a human POCG to measure glucose concentration in fluorinated porcine plasma yields results that are most similar to those produced by a biochemical analyzer. Next whole blood was collected from 24 grow-finish Yorkshire hogs that were subjected to an oral glucose tolerance test following an overnight fast to determine if the POCG can successfully measure physiologically relevant differences in circulating glucose concentrations. As expected, values obtained thirty minutes following consumption of a glucose bolus were 171% higher than fasted values as determined by the POCG (P < 0.01). These results indicate POCGs can reliably estimate circulating porcine glucose concentrations when measured in plasma.