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Do I Have Diabetes? Symptoms, Diagnosis and Types

Do I Have Diabetes? Symptoms, Diagnosis and Types
Photo Adam Ciesielski

By Nina Nazor

What are the Symptoms of Diabetes?

The most common symptoms of diabetes are the following:

  • Frequent urination
  • Excessive thirst
  • Excessive hunger
  • Feeling tired or ill
  • Sudden weight loss
  • Blurred vision
  • Slow healing of infections

Why do these symptoms appear when blood glucose is high?

When you have high blood sugar insulin cannot open the doors of the cells and glucose cannot enter the cells to be converted into energy. Your body then detects that the levels of blood glucose are too high and, since high glucose can be very toxic, your body tries to get rid of the extra glucose through your kidneys, which are the filters for your blood.
Then the kidneys pour as much glucose as possible into your urine, causing you to urinate more frequently and thus lose a lot of fluids. This makes you excessively thirsty.
Now, when your blood glucose levels are high due to your glucose not entering the cells to be used for energy, the lack of fuel makes you feel hungry and tired.
So, since your body can't get energy from the food you eat, you might also start losing weight.
The blurred vision, the slow healing of infections and other symptoms like dry skin and genital itching, are all consequences of the high levels of glucose in the blood. Read more about hyperglycemia or high blood sugar levels.

How is Diabetes Diagnosed?

There are 3 ways to know if you have diabetes:

  1. If you have symptoms of diabetes and a plasma glucose level equal or greater than 200 mg/dl (11.1 mmol/l) in a sample taken at any time of day.
  2. If the measurement of your blood glucose levels after an overnight fast (12 hours), which is called Fasting Blood Glucose Test shows a value equal or greater than 126 mg/dl (7.0 mmol/l). Normal fasting glucose levels range between 70-110 mg/dL.
  3. If the measurement of the ability of your body to handle excess sugar properly after drinking a drink with glucose shows a 2-hour plasma glucose value equal or greater than 200 mg/dl (11.1 mmol/l).

In this test, known as the Oral Glucose Tolerance Test, a blood sample is taken and you will be given a beverage containing 75 grams of glucose (or 100 grams for pregnant women). Then, your blood glucose levels will be tested again at 30 minutes, 1 hour, 2 hours and, for pregnant women, 3 hours after drinking the beverage with glucose.

Diagnosis of Gestational Diabetes

A woman has gestational diabetes when she has any two of the following values after the Glucose Tolerance Test:

  • A fasting glucose level higher than 105 mg/dl,
  • A 1-hour glucose level higher than 190 mg/dl,
  • A 2-hour glucose level higher than 165 mg/dl, or
  • A 3-hour glucose level higher than 145 mg/dl.

Impaired Fasting Glucose

A fasting glucose value equal to or greater than 110 and less than 126 mg/dl, means that you have impaired fasting glucose. This is considered a risk factor for developing diabetes in the future, but is not a positive diagnosis of diabetes.

Impaired Glucose Tolerance

Impaired glucose tolerance occurs when the 2-hour glucose are greater than or equal to 140 but less than 200 mg/dl.


If you show impaired fasting glucose or impaired glucose tolerance it is usually considered that you have pre-diabetes and this is a risk factor for developing diabetes in the future.

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