How is diabetes diagnosed? Esta entrada también está disponible en: Español (Spanish) Anyone who perceives they have symptoms of diabetes should see their healthcare professional and be tested for the disease. The following signs or symptoms are the classic ones to start thinking about whether or not I have diabetes, however, many patients do not perceive any.4 Tingling, pain, or numbness in the hands/feetWeight loss without motive Slow healing cuts/bruisesBlurry VisionExtreme FatigueUnsatisfaction even after eating Increased ThirstFrequent Urination Early detection can prevent complications of the disease. Tests and diagnosis of diabetes Anyone who perceives they have symptoms of diabetes should see their healthcare professional and be tested for the disease. A1C This test measures your average blood glucose level over the past 2 to 3 months. It is considered advantageous since you do not have to fast or drink anything.4 FASTING PLASMA GLUCOSE (FPG) It is a test that consists of measuring the level of glucose in the blood at a given time. It is best to do the exam in the morning, at least 8 hours must have passed without ingesting any type of food, at most only water.4 ORAL GLUCOSE TOLERANCE TEST (OGTT): This test measures blood glucose after you have fasted for at least 8 hours, but no more than 16 hours.5A professional will take a fasting blood glucose test, then you will drink a liquid that contains glucose. Glucose measurement is done again 2 hours after drinking the liquid.4 RANDOM PLASMA GLUCOSE (GPa) TEST: This is one of the simplest tests since it does not require fasting, it can be done at any time of the day. It is usually done when the patient has symptoms of severe diabetes.4 Your doctor will tell you which option he recommends to diagnose if you are diabetic and even prediabetic. The following table shows the values for each of the diagnostic tests. Diagnosis Diagnosis A1C test Fasting plasma glucose (FPG) Oral glucose tolerance test (OGTT) Random Plasma Glucose Test (GPa) Normal Less than 5.7% Less than 99 mg/dl Less than 140 mg/dl - Prediabetes Between 5.7% – 6.4% Between 100 mg/dl and 125 mg/dl Between 140 mg/dl and 199 mg/dl - Diabetes More than 6.5% More than 126 mg/dl More than 200 mg/dl More than 200 mg/dl Retrieved from (American Diabetes Association, 2019) CC-10758 / OCT 2025 Bibliography 4. American Diabetes Association. (2019). American Diabetes Association. Retrieved from https://www.www.diabetes.org 5. Baynes, H. (2015). Classification, Pathophysiology, Diagnosis and Management of Diabetes. Journal of Diabetes and Metabolism.