Borderline diabetes, also called prediabetes, is a condition that often develops before someone gets type 2 diabetes. It’s also known as impaired fasting glucose or glucose intolerance. It basically means your blood sugar levels are higher than normal, but they’re not quite high enough to be considered diabetes.
During the prediabetes phase, your pancreas usually still produces enough insulin in response to ingested carbohydrate. The insulin is less effective at removing the sugar from the bloodstream, though, so your blood sugar remains high. This condition is called insulin resistance.
To determine your blood glucose levels, your doctor will perform a fasting blood glucose test. This is a relatively simple test. After an overnight fast or a fast of 8 hours, your doctor will draw your blood. Using this blood sample, your sugar levels will be tested. The amount of sugar in your blood will determine if you have borderline diabetes or diabetes.
Alternatively, your doctor may instead perform a hemoglobin A1c (HbA1c) test or an oral glucose tolerance test (OGTT). HbA1c is an indicator of your blood sugar patterns over the last two to three months, so it is often a better overall picture than a single fasting blood sugar check. An HbA1c level between 5.7 and 6.4 indicates prediabetes.