OGTT is the only recommended test for detecting gestational diabetes, and the most recommended test for dysglycaemia in other conditions including type 1 diabetes and cystic fibrosis. OGTT relies on accurate measurement of blood glucose, however while glucose is a simple molecule, it is difficult to measure in many settings where OGTT is conducted. As Digostics brings the first OGTT home test kit to market in the NHS, the company is learning a lot about how gestational diabetes is being tested for and how complicated successful provision of OGTT can be. Some important aspects of OGTT will be discussed.