A comparison between point‐of‐care testing and venous glucose determination for the diagnosis of diabetes mellitus 6–12 weeks after gestational diabetes

Abstract

Aim To evaluate point-of-care-testing (POCT) for the diagnosis of Type 2 diabetes mellitus 6-12 weeks post-partum in women with gestational diabetes (GDM).Methods Post-partum glucose assessment (75-mg oral glucose tolerance test, OGTT) was performed prospectively in 122 women with GDM (1 November 2015 to 1 November 2017) at Tygerberg Hospital, Cape Town, South Africa. Individuals with known pre-existing diabetes were excluded. The accuracy and clinical utility of POCT (capillary fingerprick) were compared with laboratory plasma glucose (hexokinase and glucokinase methods). The OGTT consisted of two time points (fasting and 2 h) during which concurrent glucose samples (POCT and laboratory) were obtained. Bland-Altman plots and paired analysis were used to assess the analytical accuracy of POCT, whereas its diagnostic performance was determined using positive and negative predictive values to calculate specificity and sensitivity.Results Spearman's ranked correlation analysis indicated a strong association between POCT and laboratory glucose values at both OGTT time points (fasting, r = 0.95, P < 0.0001; 2 h, r = 0.88, P < 0.0001). Thirty-six women were diagnosed with Type 2 diabetes based on gold standard laboratory glucose levels (fasting > 7 mmol/l; 2 h > 11.1 mmol/ l). POCT correctly identified Type 2 diabetes in 78% of women (28 of 36) with a positive predictive value of 89.3% and a negative predictive value of 96.7% at the fasting time point. The sensitivity and specificity of POCT to diagnose Type 2 diabetes were 89% (fasting), 85.7% (2 h) and 96.7% (fasting), 98.5% (2 h) respectively. POCT proved less sensitive to diagnose pre-diabetes (69%) but displayed satisfactory specificity (92%) at both time points assessed.Conclusion POCT accurately identifies women with Type 2 diabetes 6-12 weeks after GDM.

Comparison of Venous and Capillary Sampling in Oral Glucose Testing for the Diagnosis of Gestational Diabetes Mellitus: A Diagnostic Accuracy Cross-Sectional Study Using Accu-Chek Inform II

“…These results are supported by a study of Coetzee where 122 women underwent OGTT eight weeks postpartum; they found a sensitivity of 89.3%, a specificity of 97%, and a PPV of 89% in fasting samples when comparing capillary and venous sampling. Similar agreements with our study were also found for the capillary sampling at 2 h [10]. The positive and negative LHRs of 16.4 and 0.2 indicate that capillary sampling at fasting and 2 h is reliable since a positive LHR above 10 indicates a high probability for correct diagnosis.…”

“…Point-of-care testing (POCT) is an attractive option compared to sending the test to a laboratory. POCT has advantages considering cost and convenience and offers the immediate availability of results and the opportunity to measure P-glucose from both venous and capillary samples [10]. Not all POCT methods have enough analytical accuracy to be used in the diagnosis of diabetes.…”

Capillary glucose concentration during oral glucose tolerance test for the diagnosis of gestational diabetes

“…However, use of POCT is common and can reduce inconvenience for patients, reduce laboratory costs, and be used in regions with difficult access to specialized medicine. 13,14,18 A recent study even evaluates the usefulness of POCT in diagnosing diabetes mellitus 6-12 weeks after gestational diabetes, 24 concluding that POCT is clinically useful in identifying women with diabetes at early postpartum evaluation. They also conclude that use of POCT can decrease the need for routine laboratory glucose testing after GDM and may reduce cost and increase the probability of postpartum glucose evaluation after GDM.…”

Observations on Glucose Excursions With the Use of a Simple Protocol for Insulin, Following Antenatal Betamethasone Administration

“…The device is whole blood calibrated; blood glucose values displayed therefore correspond to plasma. The analytical performance has previously been evaluated against rigorous laboratory criteria and did not exceed total allowable error in the fasting or postprandial state ( 14 ). The glucose results are reported in mmol/L.…”