Question 1

Is a fasting blood sugar of 100 bad?

Accepted Answer

A fasting glucose of 100 mg/dL (5.6 mmol/L) is the lower edge of the prediabetes range in many countries. It is not diabetes, but it is a useful early warning. A repeat test or an HbA1c helps confirm it, and many people bring it down with changes to activity, diet and weight.

Question 2

How long do I need to fast before a glucose test?

Accepted Answer

Usually at least 8 hours, with only water. Most people have the test first thing in the morning. Take your usual medicines unless your clinician tells you otherwise.

Question 3

Why is my blood sugar higher in the morning?

Accepted Answer

Hormones released in the early morning, such as cortisol and growth hormone, raise blood sugar before you wake up. This is called the dawn phenomenon. It is common and usually mild, but it can push a fasting result up, especially with diabetes.

Question 4

Which is better, fasting glucose or HbA1c?

Accepted Answer

They answer different questions. Fasting glucose is a snapshot of one morning; HbA1c is an average over about three months. Clinicians often use both, and one can confirm the other.