Agreement between point‐of‐care glucometry, blood gas and laboratory‐based measurement of glucose in an equine neonatal intensive care unit

Abstract

Objective: To test the agreement between 3 common methods of glucose measurement in a population of critically ill foals presenting to a neonatal intensive care unit. Design: Prospective clinical study. Setting: University large animal hospital neonatal intensive care unit. Animals: Sequentially admitted critically ill neonatal foals <30 days of age. Interventions: Venous blood obtained from a jugular vein was used for determination of blood glucose concentration using point‐of‐care (POC) glucometry (GLU), a laboratory chemistry technique (CHEM) and a multi‐electrode blood gas analyzer (BG). Paired data were compared using Lin's concordance correlation, Pearson's correlation and robust regression. Bias and limits of agreement were investigated using the technique of Bland and Altman. Measurements and main results: Concordance was significant for all comparisons and was strongest for CHEM‐BG while weakest for GLU‐BG. Pearson's correlation was excellent for all comparisons: CHEM‐BG, 0.98; GLU‐BG, 0.94; GLU‐CHEM, 0.96. All comparisons had significant robust regression coefficients: CHEM‐BG, 0.99; GLU‐BG, 0.80; GLU‐CHEM, 0.79. For Bland–Altman analysis, mean differences (mean±SD, 95% limits of agreement) were: GLU‐BG (−33±18 mg/dL, −68.6 to 1.5); GLU‐CHEM (−20±16 mg/dL, −51.0 to 10.9); CHEM‐BG (13±11 mg/dL, −8.7 to 34.7). Conclusions: This study demonstrates that glucometry has less than ideal agreement with a laboratory standard and another POC test, blood gas analysis. These differences may be clinically important and decisions regarding management of glucose concentrations in critically ill foals should be made with these differences in mind.

Comparison of the Accu‐Chek Aviva Point‐of‐Care Glucometer with Blood Gas and Laboratory Methods of Analysis of Glucose Measurement in Equine Emergency Patients

“…A recent study of glucometry in the critically ill equine neonate clearly demonstrated the need for thorough investigation of glucometry in veterinary patients. In that study, POC glucometry with whole blood was, on average, 20 mg/dL below the laboratory standard and 33 mg/dL below measurements with a multielectrode blood gas analyzer 8 . In addition, the 95% limits of agreement of the glucometer tested were extremely wide, 8 demonstrating that the glucometer had less than ideal agreement with the laboratory standard, and may therefore be inappropriate for use in a clinical setting.…”

“…Other factors that may affect accuracy include alterations of the filters used in glucometer strips to separate the red blood cells from plasma. These may be affected by the increased tendency of equine red blood cells to rouleaux formation and, in addition, microclot formation, hemolysis, or inflammatory phenomena such as high fibrinogen concentration 8,25 . Reagent test strip performance may vary by lot and individual monitors by model.…”

“…Reagent test strip performance may vary by lot and individual monitors by model. In addition, the age and handling of the reagent strips may reduce their reliability, especially when exposed to humidity 8,26,27 . In the present study, the same glucometer was used throughout the study, the reagent strips were from the same lot number, and the glucometer and reagent strips were stored in a temperature‐and humidity‐controlled environment in order to reduce these potential effects.…”

“…POC glucose was measured with a commercially available glucometer designed for use in humans c . The POC glucometer uses a glucose dehydrogenase‐based technology similar to that used in a previous POC glucometry study in neonatal foals 8 . A small amount of whole blood was retained for immediate analysis performed with the POC glucometer c (POC/WB) by placing a drop of mixed blood on a preplaced reagent strip after collection, using the glucometer in a routine manner according to the manufacturer's instructions.…”

Evaluation of a Veterinary Glucometer for Use in Horses

“…Presenting complaints for horses considered healthy on admission included nonseptic, noncatastrophic limb injury (11), lameness examination (8), dental examination (3), pre-operative cryptorchidectomy or ovariectomy (2), and head shaking (1). Presenting complaints for horses admitted for emergency evaluation and considered critically ill included colic (15), severe local sepsis with concurrent signs of systemic illness (3), retained placenta (2), placentitis (1), colitis (1), laminitis (1), influenza-associated acute respiratory distress syndrome (1), and acute blood loss (1). Foals had a median age of 4 days [IQR: 1-6 days].…”