Diagnosis of Gestational Diabetes Mellitus with Point-of-Care Methods for Glucose versus Hospital Laboratory Method Using Isotope Dilution Gas Chromatography-Mass Spectrometry as Reference

Abstract EN

Background.

In Sweden, both glucose analyzers in accredited laboratories and point-of-care glucose devices are used for gestational diabetes mellitus (GDM) diagnosis.

The aim of this study was to compare the diagnostic performance of the HemoCue Glucose 201+ (HC201+) and RT (HC201RT) systems with that of the hospital central laboratory hexokinase method (CL) based on lyophilized citrate tubes, using the isotope dilution gas chromatography-mass spectrometry (ID GC-MS) as reference.

Methods.

A 75 g oral glucose tolerance test was performed on 135 women screened positive for GDM.

Diagnosis was based on the World Health Organization 2013 diagnostic thresholds for fasting (n=135), 1 h (n=52), and 2 h (n=135) glucose measurements.

Bland-Altman analysis and surveillance error grids were used to evaluate analytical and clinical accuracy.

Results.

Significantly more women were diagnosed with GDM by HC201+ (80%) and CL (80%) than with the reference (65%, P<0.001) based on fasting and/or 2 h thresholds, whereas the percentage diagnosed by HC201RT (60%) did not differ significantly from the reference.

In Bland-Altman analysis, a positive bias was observed for HC201+ (4.2%) and CL (6.1%) and a negative bias for HC201RT (−1.8%).

In the surveillance error grid, 95.9% of the HC201+ values were in the no-risk zone as compared to 98.1% for HC201RT and 97.5% for CL.

Conclusions.

A substantial positive bias was found for CL measurements resulting in overdiagnosis of GDM.

Our findings suggest better performance of HC201RT than HC201+ in GDM diagnosis.

The results may have possible implications for GDM diagnosis in Sweden and require further elucidation.