JMIR Publications

ABSTRACT

Background:

In the UK, women at high risk of GDM are offered a 75g oral glucose tolerance test (OGTT) at 24-28 weeks gestation, which requires the patient to attend a clinical facility. The GTT@home oral glucose tolerance test device is an electronic device with potential to enable patients to perform an OGTT at home using capillary blood samples.

Objective:

To determine the accuracy of the GTT@home device compared to routine NHS laboratory reference method using blood samples during an oral glucose tolerance test (OGTT) from pregnant women at high risk of developing gestational diabetes (GDM).

Methods:

65 women (>18years), at high risk for GDM (NICE guidelines) were recruited. Following an overnight fast, participants attended for a 75g OGTT. Fasting and 2-hour capillary glucose was measured using the GTT@home device with corresponding venous samples measured in the laboratory.

Results:

61/65 devices gave complete data for analysis. GTT@home overall bias was +0.16 mmol/L. Correlation of clinical performance of the two methods using surveillance error grid showed 79.8% of results in the lowest, 16.9% in the ‘slight, lower’ and 2.4% in the ‘slight, higher’ risk categories. Only 0.8% were ‘moderate, lower’ risk and none were in any higher risk categories. There was agreement in classification in 54/61 cases. The GTT@home device under-classified 2 cases and over-classified 5 cases.

Conclusions:

The GTT@home device worked well in a controlled, ante-natal clinical setting. Differences in classification observed were generally due to small differences in glucose values close to diagnostic cut-offs. The GTT@home device shows promise for home testing of glucose tolerance in pregnant women.