Fasting blood sugarFBS, Fasting plasma glucoseFasting blood sugar is the glucose level in blood after at least eight hours without food or sweetened drink. It is the simplest and cheapest test for diabetes, and one of the three that can diagnose it.
Random blood sugar
Also known as RBS, Random plasma glucose, Random blood glucose
A blood sugar taken at any time of day without fasting. A result of 200 mg/dL or more, together with symptoms, points to diabetes.
It is the quickest diabetes test there is, needing no preparation, which is why it is the one usually done when someone arrives with thirst, weight loss and frequent urination.
A normal random reading does not rule diabetes out — blood sugar moves through the day. A or is needed to be sure.
Related terms
- HbA1cGlycated haemoglobin, A1cHbA1c measures the proportion of haemoglobin that has sugar stuck to it, which reflects the average blood glucose over roughly the past three months. It needs no fasting and is used both to diagnose diabetes and to judge how well it is controlled.
- Postprandial blood sugarAfter-meal blood sugar, PP sugarBlood sugar measured two hours after starting a meal. It shows how well your body handled that particular food.