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Type 2 diabetes has long been on the rise—it is now the fastest-growing chronic condition in Australia—so it makes sense that its lesser-known sibling, prediabetes, is also increasing - some two million Aussies have it and it;s estimated that half of them don't know it. That's a problem, because if you don't know you have it you likely aren't making the changes needed to ward off the full-blown disease.

Prediabetes is a borderline condition in which your blood sugar is consistently high but not high enough to be considered diabetes. The easiest way to determine if you have it is to get a simple blood test. The most accurate one is the A1C test, which determines the percentage of glucose (sugar) that's attached to the oxygen-carrying protein haemoglobin in your blood.

"It's a good indicator of what your blood sugar has been like for the past two or three months," says endocrinologist Dr Loren Greene. A score of 5.9 and below is considered normal. Anything between 5.7 and 6.4 is considered prediabetes, and 6.4 and above is full-blown diabetes.

 Although tests such as the A1C can certainly tell you if you're headed for trouble, it's also important to pay attention to other clues. In some cases, even if your test results come back normal, you might still be prediabetic. "Prediabetes is like most 'pre' anything—nobody has an exact, precise definition," says Greene. That's why red flags like excessive thirst and frequent urination are worth taking seriously. Some other signs that warrant a call to your doctor, and probably a blood sugar test, include: