Abstract: 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. Methods: Multicenter, prospective, experimental study, conducted between March 2019 and June 2020. Methods: Four university teaching hospitals and 1 private referral hospital. Methods: Fifty-four hospitalized neonatal (≤30 days of age) foals. Methods: 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. 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.
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Overview
This study assessed the accuracy of point-of-care (POC) glucometer readings from capillary and venous blood in hospitalized neonatal foals by comparing them to standard laboratory glucose measurements.
Background and Purpose
Neonatal foals often require glucose monitoring to manage hypoglycemia or other metabolic conditions during hospitalization.
Point-of-care glucometers are frequently used in clinical settings for rapid glucose measurement.
However, the reliability of POC glucometers compared to laboratory-based glucose assays, especially in neonatal foals, had not been well established.
The study aimed to evaluate how well POC glucose results from capillary (muzzle) and venous (jugular) blood matched standard laboratory glucose values.
Study Design and Setting
A prospective, multicenter experimental study conducted from March 2019 to June 2020.
Included five institutions: four university teaching hospitals and one private referral hospital.
Fifty-four hospitalized neonatal foals (age ≤ 30 days) were enrolled.
Each foal had simultaneous sampling of capillary blood from the muzzle and venous blood from the jugular vein for POC glucometer readings.
Venous samples were also sent for standard laboratory glucose measurement using a colorimetric, glucose oxidase method (referred to as LABGLU).
Samples were collected at admission/enrollment and once more during hospitalization.
Mean arterial pressure and hematocrit were recorded concurrently as physiological parameters that might influence glucose readings.
Key Measurements and Analysis
Glucose levels measured by:
POC glucometer from muzzle capillary blood (POCMUZ).
POC glucometer from jugular venous blood (POCJUG).
Standard laboratory assay from jugular venous blood (LABGLU).
Statistical method used to compare measurements was Bland-Altman analysis for bias and limits of agreement between methods.
Concordance correlation coefficients (with 95% confidence intervals) were calculated to assess agreement between the POC methods and LABGLU.
Classification accuracy for hypoglycemia was assessed by comparing how many hypoglycemic foals (per LABGLU) were misclassified as normal (euglycemic) by the POC methods.
Results
Bland-Altman bias (mean difference) between POCJUG and LABGLU was -28.0 mg/dL, indicating POCJUG tended to underestimate glucose compared to LABGLU on average.
POCMUZ had a smaller mean bias of -8.2 mg/dL versus LABGLU but still showed wide limits of agreement.
The bias between POCMUZ and POCJUG was 18.8 mg/dL, showing they also differed between each other.
A substantial proportion of samples showed significant discrepancies:
63.5% of POCJUG readings deviated from LABGLU by more than ±15 mg/dL (for low glucose) or ±15% (for higher glucose).
45.2% of POCMUZ readings exceeded these thresholds.
Concordance correlation coefficients indicated fair but not excellent agreement:
POCJUG vs LABGLU: 0.75 (moderate agreement)
POCMUZ vs LABGLU: 0.71 (slightly lower agreement)
Hypoglycemia misclassification:
50% (14 out of 28) hypoglycemic foals by LABGLU were classified as normal by POCJUG.
18% (5 out of 28) hypoglycemics were misclassified by POCMUZ.
Conclusions and Clinical Implications
The POC glucometer evaluated in this study lacked sufficient agreement with the standard laboratory glucose assay in neonatal foals.
Wide limits of agreement mean that individual POC measurements could deviate substantially from actual blood glucose levels.
Inaccurate POC glucose readings may compromise clinical decision-making, particularly in managing glycemic control for critical neonatal foals.
Underdiagnosis of hypoglycemia due to false normal POC readings is a significant risk, which can negatively impact patient outcomes.
Clinicians should exercise caution in relying solely on POC glucometer results and consider confirmatory laboratory testing when precise glucose measurements are essential.
Cite This Article
APA
Dias Moreira AS, Weng HY, Hostnik LD, Beasley EM, Peek SF, Munsterman AS.
(2024).
Evaluation of point-of-care capillary and venous blood glucose concentrations in hospitalized neonatal foals.
J Vet Emerg Crit Care (San Antonio), 34(6), 570-578.
https://doi.org/10.1111/vec.13429
Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
Weng, Hsin-Yi
Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA.
Hostnik, Laura D
Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
Beasley, Erin M
Department of Large Animal Medicine, University of Georgia, Athens, Georgia, USA.
Peek, Simon F
Department of Medical Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Munsterman, Amelia S
Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
MeSH Terms
Animals
Horses / blood
Animals, Newborn / blood
Blood Glucose / analysis
Point-of-Care Systems
Prospective Studies
Female
Male
Hospitalization
Capillaries
Grant Funding
School of Veterinary Medicine at the University of Wisconsin-Madison
Companion Animal Fund Research Grant, School of Veterinary Medicine, University of Wisconsin-Madison
Conflict of Interest Statement
Dr. Munsterman is an Assistant Editor of the Journal but only participated in the peer review process as an author. There are no conflicts of interest to disclose, financial or otherwise.
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