Evaluation of an Electrochemical Point‐of‐Care Meter for Measuring Glucose Concentration in Blood from Periparturient Dairy Cattle

Abstract

BackgroundThe Precision Xtra® meter is a promising low cost electrochemical point‐of‐care unit for measuring blood glucose concentration ([gluc]) in cattle blood. The meter uses an algorithm that assumes the intra‐erythrocyte [gluc] equals the plasma [gluc] on a molal basis, and that the hematocrit is similar in humans and cattle.ObjectivesThe primary objective was to determine the accuracy of the meter for measuring plasma [gluc] in dairy cattle. Secondary objectives were to characterize the influence of hematocrit and sample temperature on the measured value for [gluc].AnimalsA total of 106 periparturient Holstein‐Friesian cattle.MethodsBlood and plasma samples (1,109) were obtained and Deming regression and Bland–Altman plots were used to determine the accuracy of the meter against the reference method (plasma hexokinase assay). Multivariable regression and linear regression were used to determine the effect of hematocrit and sample temperature on the plasma [gluc] measured by the meter.ResultsIntra‐erythrocyte [gluc] was 18% of plasma [gluc] on a molar basis. Sample temperature had a significant linear effect on plasma [gluc] as measured by the meter for 3/5 plasma samples when measured [gluc] > 160 mg/dL.Conclusions and clinical importanceThe meter utilizes an algorithm that is optimized for human blood and is inaccurate when applied to bovine blood. Until a cattle‐specific algorithm is developed, we recommend using plasma as the analyte instead of blood and calculating plasma [gluc] using the equation: [gluc] = 0.66 × [gluc]p‐meter + 15, where [gluc]p‐meter is the value reported by the meter. If blood is measured, then we recommend using the equation: [gluc] = 0.90 × [gluc]b‐meter + 15.

Clinical Utility of Plasma Fructosamine Concentration as a Hypoglycemic Biomarker during Early Lactation in Dairy Cattle

“…The study reported here was part of a larger study investigating energy and potassium homeostasis in the periparturient period, and the prediction of parturition and dystocia in Holstein–Friesian cattle. These results have been published elsewhere …”

“…Plasma [gluc] was measured using a Precision Xtra point‐of‐care meter. Plasma [gluc] was calculated from the Precision Xtra reading for plasma [gluc] in mg/dL ([gluc] p‐meter ) using the following equation developed by our laboratory: …”

“…These results have been published elsewhere. [32][33][34][35][36] Animals, Housing, and Feeding An observational study was conducted using a convenience sample of 103 periparturient Holstein-Friesian cattle (32 primiparous, 71 multiparous) from the Purdue University Dairy Research and Education Center over a 10-month period between May 29, 2012 and March 29, 2013. Enrolled cows were moved from an outdoor dry lot to temperature controlled (16-278C) individual box stalls (3.1 3 3.1 m) at 4 days before the estimated parturition date based on breeding records and pregnancy diagnosis at approximately 40 days after breeding.…”

Characterization of the analytic performance of an electrochemical point‐of‐care meter for measuring β‐hydroxybutyrate concentration in blood and plasma from periparturient dairy cattle

“…Blood samples were obtained daily from the coccygeal vein or artery at approximately 09:00 am on days À4, À3, À2, À1, 0, 1, 2, 3, 7, 14, 21, and 28 relative to calving (day 0), as described elsewhere. 39 The study reported here was part of larger study investigating energy, calcium, and potassium homeostasis in the periparturient period, and the prediction of parturition and dystocia in Holstein-Friesian cattle. Further results have been published elsewhere.…”

“…Further results have been published elsewhere. [39][40][41][42] Immediately after blood collection, BHB was measured in a drop of nonheparinized blood from the tip of the vacutainer needle using an electronic hand-held meter (Precision Xtra; Blood Glucose and Ketone Monitoring System; Abbott Diabetes Care Inc., Alameda, CA, USA). Both coded ketone test strips that included a calibrator strip with each new box of test strips, and noncoded ketone test strips were used.…”