How is diabetes diagnosed?

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The following signs or symptoms are the classics to start thinking about whether or not you have diabetes, however, many patients do not perceive any of these. 4 .

Frequent Urination

Increased Thirst 

Unsatisfaction even after eating 

Extreme Fatigue

Blurry Vision

Slow healing cuts/bruises

Weight loss without motive 

Tingling, pain, or numbness in the hands/feet.


Anyone who perceives symptoms of diabetes should consult with their professional health care provider and be checked for the disease.

  • Glycosylated hemoglobin Test (A1C): These test measures provide the average level of glucose in the blood during the last 2 or 3 months. It is considered beneficial as you do not have to fast or drink anything.4
  • Fasting Plasma Glucose (FPG):  It is a test that consists of measuring the glucose level in the blood at any time. It is best to take the test in the morning. They must have spent at least 8 hours without ingestion of any kind of food, only water at most. 4
  • Oral Glucose Tolerance Test (OGT): A professional will take a fasting blood glucose test, later you must drink a liquid that contains glucose. Again your glucose will be measured 2 hours after drinking the liquid. 
  • Random Plasma Glucose Test (RPG):  This is the simplest kind of test because 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. Your doctor will tell you which option he recommends for diagnosis.4

Your doctor will recommend you which option is the best to know if you have diabetes or even prediabetes. The following chart shows the value of each of the diagnostic tests.


  1. American Diabetes Association. (2019). American Diabetes Association. Retrieved from
  2. Baynes, H. (2015). Classification, Pathophysiology, Diagnosis and Management of Diabetes. Journal of Diabetes and Metabolism.

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