Validation of Glucometer Technology for Measurement of Glycaemia during Glucose Tolerance Tests and Endotoxin Challenge in Pigs

• Published in: Journal of animal science 2018-03, Vol.96, p.82-82
• Main Authors: Nunnelley, W Z, Maxwell, H S, Bayne, J E, Brandebourg, T D
• Format: Article
• Language: English
• Subjects: Analyzers; Biochemistry; Blood; Blood circulation; Blood glucose; Cell size; Correlation analysis; Estimates; Fluorination; Glucose; Glucose tolerance; Hogs; Injection; Measuring instruments; Physiology; Plasma; Rectum; Technology
• ISSN: 0021-8812; 1525-3163

Glucometers are portable, require small sample volumes, and yield rapid estimates of glycaemia. However, differences in packed cell volume of whole blood between species potentially confound estimates of glucose concentration compared to clinical biochemical analyzers (BA). Our objective was to determine the correlation between glucometer estimates of glucose concentration in serum, plasma, and whole blood compared to biochemical analyzer values and then to use the optimal sample handling procedure to track changes during physiological challenges to euglycaemia. Blood samples were collected via jugular venipuncture from 152 Yorkshire barrows and gilts between 8 to 12 weeks of age. Glucose concentration was measured in whole blood, serum, plasma, and fluorinated plasma. Values were compared by Pearson correlation and Bland-Altman analysis. Glucometer estimates of glycaemia in whole blood were highly variable and poorly correlated with BA values (r2=0.34). Correlations of serum and plasma glucometer values with BA values were significantly stronger (serum, r2=0.57; plasma, r2=0.64). Glucometer values obtained in fluorinated plasma correlated the strongest with BA values (r2=0.89). Bland-Altman analysis likewise revealed that glucometer estimates of glycaemia in fluorinated plasma were most similar to those obtained by BA. Mean differences in glucose concentrations determined by BA and glucometer 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 glucometer technology can reliably reproduce biochemical analyzer estimates of glycaemia when measured in fluorinated plasma. Next this protocol was used in market weight pigs to monitor glycaemia under physiological challenges, represented by glucose tolerance tests (GTT) to mimic postprandial conditions and endotoxin challenges to mimic acute infection. For GTT, pigs (n =4) were fasted for 12 hours, and then 0.3 g/ kg BW glucose was infused. Venous blood was collected at regular intervals for 3 hours post-infusion. Circulating glucose concentration increased 5-fold by 30 minutes after infusion and returned to baseline by 120 minutes. Values obtained by glucometer and BA were not different (P > 0.77). Intramuscular injection of 50 µg/kg BW endotoxin induced a febrile response as rectal temperatures increased 3 degrees Celsius by 1 hour after injection, concomitant with a 43% decrease in glucose concentration. Glucose values obtained