What is diabetes screening done with?

A clinician may request an HbA1c blood test, which reflects average glucose over the preceding period, or a blood glucose test taken at a specified time. In some situations, an oral glucose tolerance test is used: you drink a measured glucose solution and provide timed blood samples.

Screening is designed to find diabetes or an increased likelihood of developing it before clear symptoms appear. A [Continuous Glucose Monitor](/technology/continuous-glucose-monitor/) is mainly a monitoring device and is not usually the first test used to screen someone who has no diagnosis.

Check whether your appointment requires fasting; preparation depends on the test. Tell the clinician about pregnancy, recent illness, medicines, and conditions that may affect blood results. A result outside the expected range may need confirmation or a different test before a diagnosis is made.

Read about [Diabetes Screening](/treatments/diagnostics-and-screening/diabetes-screening/) for context, then keep a record of the test name and whether you were asked to fast. Arrange follow-up so the result is explained in relation to your health.

Screening is generally arranged in advance, but seek prompt medical advice for marked thirst with frequent urination, vomiting, dehydration, unusual drowsiness, confusion, or rapid breathing. Urgent assessment is also appropriate if you feel seriously unwell while waiting for a planned test.

Ask which test you need, whether fasting is required, when results will be available, whether an abnormal result needs confirmation, and how often screening should be repeated for your risk profile.