Objective: To assess the clinical utility of point-of-care (POC) capillary blood glucose (CBG) testing in the assessment of gestational diabetes mellitus (GDM) during oral glucose tolerance test (OGTT).
Design: Prospective cohort study.
Setting: Antenatal clinics at King's College Hospital.
Population: Women screened for GDM between March and June 2020.
Methods: The CBG was measured using the POC StatStrip® test and the venous plasma glucose (VPG) was measured by Roche analyser (Cobas 8000 c702). GDM was diagnosed based on the 2015 National Institute for Health and Clinical Excellence (NICE) Clinical Guideline criteria. The two methods were compared statistically using Analyse-It 5.40.2.
Main outcome measures: Diagnostic sensitivity, specificity, positive and negative predictive values (PPV and NPV) for the POC StatStrip® test, compared with VPG measured by reference laboratory method.
Results: A total of 230 women were included. The number and percentage of women with glucose concentrations above the GDM threshold using the POC StatStrip® test versus laboratory VPG measurement was 15 (6.5%) versus eight (3.4%) at fasting and 105 (45.6%) versus 72 (31.1%) at 2 h, respectively. The sensitivity and specificity values (and 95% CIs) for the POC StatStrip® test were 88% (52%-99%) and 97% (93%-98%) at fasting and 97% (91%-99%) and 79% (71%-84%) at 2 h, respectively. However, the specificity and the NPV for the POC StatStrip® test for concentrations of ≤5.0 mmol/L at fasting or <7.5 mmol/L at 2 h were 100%, and the sensitivity and the PPV for concentrations of >9.5 mmol/L at 2 h were 100%.
Conclusions: In our cohort the POC measurement of CBG cannot entirely replace the laboratory method for the OGTT; however, it can be used to rule out/rule in GDM for glucose concentrations of ≤5.0 mmol/L at fasting or <7.5/>9.5 mmol/L at 2 h.
Keywords: capillary blood glucose; gestational diabetes mellitus; oral glucose tolerance test; point of care; venous plasma glucose.
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