Testing for prediabetes: your first step out of the grey zone

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Two in three South Africans are living with pre-diabetes, but the condition is reversible.

That’s why screening is so important – it helps detect problems early allowing you to take action now.

Dr Martin de Villiers, a physician specialising in internal medicine at Mediclinic Cape Town, explains that prediabetes is a condition where the levels of glucose in your blood are higher than normal, but not high enough for you to be considered diabetic. “A normal level of blood sugar is usually around 5.4. If it’s between 5.6 and 7, it could be a warning sign that your body isn’t responding to insulin properly,” he says.

According to South Africans with Diabetes, two-thirds of the population are prediabetic.

People with prediabetes usually don’t have the typical diabetes symptoms like tiredness, itchy dry skin, needing to urinate a lot, being very thirsty, dry mouth, or blurry vision. But these can occur if blood sugar isn’t brought back to normal. If prediabetes turns into full diabetes, it can lead to serious problems like stroke, heart disease, nerve and eye damage, high blood pressure and cholesterol, and in severe cases, even amputations.

Types of tests for prediabetes

The problem is that prediabetes usually has no symptoms, so people often don’t know they’re at risk. But a doctor may suggest tests if there are warning signs, like sudden weight gain or a family history of diabetes. People who are overweight or have heart problems should also get checked.

Haemoglobin A1C (HbA1C) test: Dr De Villiers says the HbA1C test is the most accurate way to test for prediabetes. A small blood sample is taken, so your doctor can measure the amount of glucose that has attached to red blood cells over a period of two or three months.

He says he prefers this test because it shows your blood sugar over time, not just at one moment. “Making a diagnosis is like putting together a puzzle to see the full picture. The test results are one piece, but we also look at other clues, like whether you’ve gained a lot of weight over the year, become less active, or if your blood sugar is higher than it was last year.”

Fasting blood sugar (glucose) test: Your doctor may also recommend a fasting blood sugar/glucose test. This requires avoiding food for 8-12 hours the night before, although you may still drink water. The test is usually performed in the morning. 

Glucose tolerance test: This test may be suggested if your doctor wants to see how your body handles sugar. First, a blood sample is taken after fasting. Then you’ll drink a sugary liquid, and more blood samples will be taken every 30-60 minutes. These results show how your body processes sugar and whether it’s struggling to manage glucose in your blood.

Random glucose test: Can also be used to provide a picture of your blood glucose levels at any point in the day. Although this test provides information quickly about whether your body needs insulin, tests that measure glucose over a longer period are generally considered more effective.

Reversing prediabetes

The good news is that prediabetes can be reversed once it’s diagnosed. This might involve important/effective lifestyle changes like losing weight and exercising, but for some people, medication may be needed. Your doctor can guide you on the best approach, says Dr De Villiers.