Different glucose analyzers report different glucose concentration values in term newborns

Area of Science:

• Clinical Chemistry
• Neonatal Medicine
• Laboratory Diagnostics

Background:

• Neonatal hypoglycemia guidelines use glucose thresholds from studies with Beckman/Yellow Springs analyzers.
• Most U.S. labs (76%) now use Vitros Glucose Analyzers.
• A ~5% bias exists between Beckman and Vitros analyzers, potentially affecting clinical decisions.

Purpose of the Study:

• To compare plasma glucose concentrations between Beckman and Vitros analyzers in newborns.
• To assess instrument bias in neonatal glucose measurements.

Main Methods:

• Compared plasma glucose in 1,987 newborns within 3 hours of birth using Beckman (n=904) and Vitros (n=1,083) analyzers.
• Utilized nonlinear cubic spline models to analyze glucose concentration over time.
• Performed method comparison studies on adult samples.

Main Results:

• Paralleled glucose concentration patterns between analyzers with no confidence interval overlap.
• Identified a constant bias of approximately +5 mg/dL favoring Beckman.
• Adult sample studies showed a +4.2-7.4 mg/dL bias for Beckman vs. Vitros.

Conclusions:

• Beckman analyzers yield ~5 mg/dL higher glucose readings than Vitros analyzers in term newborns.
• A Beckman reading of 45 mg/dL may equate to a Vitros reading of 40 mg/dL.
• Awareness of analyzer type and potential bias is crucial for managing neonatal hypoglycemia using published guidelines.