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  • Writer's pictureDr. Karuturi Subrahmanyam

How to diagnose diabetes?


Diabetes is a condition that affects how your body uses glucose (sugar), the main source of energy for your cells. Having too much glucose in your blood can cause serious health problems, such as damage to your eyes, kidneys, nerves, and heart. There are different types of diabetes, such as type 1, type 2, and gestational diabetes. Each type has different causes and treatments.


The only way to know if you have diabetes is to get tested by a doctor. They will use a blood test to measure your blood glucose level and see if it is higher than the normal range. You may need to fast (not eat anything) for a certain period of time before the test, or you may have a random test at any time of the day.


Sometimes, you may need more than one test to confirm your diagnosis.


The following are some common blood tests used to diagnose diabetes:

  • A1C test. This test shows your average blood glucose level for the past 2 to 3 months. It measures the percentage of glucose attached to hemoglobin, a protein in your red blood cells. The higher your blood glucose levels, the more hemoglobin you’ll have with sugar attached. An A1C level of 6.5% or higher on two separate tests means that you have diabetes. An A1C between 5.7% and 6.4% means that you have prediabetes, which means you are at risk of developing diabetes in the future. Below 5.7% is considered normal.

  • Fasting blood sugar test. This test measures your blood glucose level after you haven’t eaten anything for at least 8 hours. A fasting blood sugar level less than 100 mg/dL is normal. A fasting blood sugar level from 100 to 125 mg/dL is considered prediabetes. If it’s 126 mg/dL or higher on two separate tests, you have diabetes.

  • Glucose tolerance test. For this test, you fast overnight and then have a fasting blood sugar test. Then you drink a sugary liquid, and your blood glucose levels are tested regularly for the next 2 hours. A blood glucose level less than 140 mg/dL is normal. A reading of more than 200 mg/dL after 2 hours means you have diabetes. A reading between 140 and 199 mg/dL means you have prediabetes.

  • Random blood sugar test. This test measures your blood glucose level at any time of the day, no matter when you last ate. A blood glucose level of 200 mg/dL or higher suggests diabetes.


If your doctor thinks you may have type 1 diabetes, they may also test your urine to look for the presence of ketones, which are substances produced when your body breaks down fat for energy. Having ketones in your urine can be a sign of diabetic ketoacidosis, a serious and potentially life-threatening complication of type 1 diabetes.


If you have diabetes, your doctor will work with you to create a treatment plan that suits your needs and goals. You may need to take medications to lower your blood glucose levels. You will also need to monitor your blood glucose regularly, eat a healthy diet, exercise regularly, and avoid smoking and alcohol. Managing your diabetes can help you prevent or delay the long-term complications of the disease.


If you have prediabetes, you can take steps to prevent or delay the onset of type 2 diabetes. These include losing weight if you are overweight or obese, eating a balanced diet that is low in added sugars and fats, increasing your physical activity, and quitting smoking if you smoke. Your doctor may also prescribe medication to help lower your blood glucose levels.


If you have symptoms of diabetes, such as feeling thirsty, hungry, or tired more often than usual, urinating more frequently, having blurred vision, or losing weight without trying, you should see your doctor as soon as possible. Early diagnosis and treatment can help you avoid serious health problems and improve your quality of life.


Dr. Karuturi Subrahmanyam, MD, FRCP (London), FACP (USA)

Internal Medicine Specialist


Kify Hospital

Danavaipeta

Rajahmundry

Phone : 85000 23456

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