Evaluation of point-of-care capillary and venous blood glucose concentrations in hospitalized neonatal foals

Objective

To compare glucose measurements from capillary and venous blood samples using a point-of-care (POC) glucometer with a standard laboratory (colorimetric, glucose oxidase) assay (LABGLU) in a population of hospitalized, neonatal foals.

Design

Multicenter, prospective, experimental study, conducted between March 2019 and June 2020.

Setting

Four university teaching hospitals and 1 private referral hospital.

Animals

Fifty-four hospitalized neonatal (≤30 days of age) foals.

Interventions

Simultaneous capillary (muzzle, POCMUZ) and venous (jugular, POCJUG) blood samples were obtained to determine POC glucose concentrations. Venous samples were also analyzed by LABGLU. Each foal was sampled at the time of enrollment or admission to the hospital and at 1 subsequent point during hospitalization. Indirect mean arterial pressure and hematocrit were concurrently recorded.

Measurements and Main Results

Bland–Altman analysis showed a mean bias (95% limits of agreement) of −28.0 (−88.6 to 32.6) mg/dL for comparison of POCJUG with LABGLU, −8.2 (−94.3 to 78.0) mg/dL for POCMUZ and LABGLU, and 18.8 (−44.4 to 82.0) mg/dL for POCMUZ and POCJUG. A total of 63.5% of the POCJUG and 45.2% of the POCMUZ samples exceeded the reference value by ±15 mg/dL (for LABGLU samples <75 mg/dL) or ±15% (for LABGLU samples ≥75mg/dL). Concordance correlation coefficient (95% confidence interval [CI]) indicated a fair agreement between POCJUG and LABGLU (0.75, 95% CI: 0.66–0.82) and between POCMUZ and LABGLU (0.71, 95% CI: 0.58–0.80). Fifty percent (14/28) of hypoglycemic foals on the reference method were incorrectly classified as euglycemic by POCJUG, and 5 of 28 were incorrectly classified by POCMUZ.

Conclusions

In the sampled population, the chosen POC glucometer lacked agreement with the standard laboratory measurement. Limits of agreement were wide for both POCJUG and POCMUZ. Inaccuracies in POC results could impact decision-making in the clinical management of glycemic control in hospitalized neonatal foals and, importantly, increase the risk of hypoglycemic events being underdiagnosed in critical patients.