If you have a family history of high blood sugar, your doctor may want to perform a diabetes test or two to track your potential for developing types of diabetes. If you’re wondering what blood tests indicate diabetes or what helps diagnose the disease, there are actually a few tests that healthcare professionals can perform to let you know the status of your blood sugar.
Navigating the world of high blood sugar can not only be overwhelming, but downright stressful. But, it’s more common than you might think. According to the Centers for Disease Control and Prevention (CDC), one in three American adults has prediabetes. And of that number, 80% don’t even know they are prediabetic.
Now we know that no one wants to be pushed and prodded unnecessarily. But knowing how to test for diabetes and what tests to order if you’re worried about developing type 1 diabetes, type 2 diabetes, gestational diabetes, or other types of diabetes can save you and your doctor a precious time. Plus, it will help you feel more in control of your care.
Here, the experts explain what a diabetes test is, the different types of tests available, and what the results of each test mean.
Perhaps one of the best-known diabetes tests, “Hemoglobin A1C helps understand if you’ve had high blood sugar over a three-month period,” says Deena Adimoolam, MD, specialist in endocrinology and preventive medicine. “It’s a simple blood test that can help make the diagnosis quickly. This is the gold standard for diagnosing diabetes and if abnormal should be followed up every three months.
As for which results mean a diagnosis of diabetes, the American Diabetes Association (ADA) says anyone with a result of 6.5% or higher is considered diabetic. Meanwhile, anyone with a result of 5.7% to 6.4% can be considered prediabetic, and those with a result of 5.6% or lower are considered normal.
Fasting blood glucose test (fasting blood sugar)
“Fasting blood sugar helps to understand if you are at risk for prediabetes or diabetes, but does not establish the diagnosis,” says Dr. Adimoolam. Meanwhile, Jacqueline Lonier, MD, assistant professor of medicine at the CUIMC Naomi Berrie Diabetes Center, says, “Fasting blood sugar is measured after not eating or drinking anything except water for at least eight hours before testing. . Diabetes is diagnosed when fasting blood sugar is above 125 mg/dL. To put things into perspective, the ADA states that a normal fasting blood sugar reading is below 100 mg/dL, while prediabetes is considered 100 mg/dL to 125 mg/dL.
Glucose tolerance test
According to Dr. Adimoolam, an oral blood sugar test is one way to diagnose high blood sugar during pregnancy. And Dr. Lonier explains that an “oral glucose tolerance test measures blood sugar two hours after drinking a standardized solution containing 75 grams of glucose.” She says diabetes is diagnosed when blood sugar after the two-hour mark is 200 mg/dL or higher. Normal blood glucose levels should be below 140 mg/dL and prediabetic numbers 140 mg/dL to 199 mg/dL.
Random blood sugar test
Another test that could identify something wrong with your blood sugar is a random blood sugar test. “Diabetes can also be diagnosed when a random blood sugar level is greater than or equal to 200 mg/dL as part of symptoms of hyperglycemia,” says Dr. Lonier. So, if someone were to randomly prick their finger and use a glucometer to check their blood sugar, and the reading was greater than or equal to 200 mg/dL, it could indicate diabetes when certain symptoms are also present. Those symptoms, she notes, are excessive thirst, frequent urination, blurred vision and weight loss.
Presence of certain antibodies in the diagnosis of type 1 diabetes
Although this test does not necessarily mean diabetes, a positive test may indicate that a person could develop type 1 diabetes or is at higher risk of developing the disease. “Since type 1 diabetes is also an autoimmune disease, we can check for the presence of antibodies against glutamic acid decarboxylase, zinc transporters and insulin,” explains. Dr Adimoolam. However, this does not mean that if you have these antibodies you are automatically a type 1 diabetic. Rather, it means that you could develop type 1 or are at a higher risk of having the disease.