Blood sugar and diabetes checks

High blood sugar levels can cause short term effects but will not cause damage to major organs.  Short term effects may include:

  • feeling tired and weak
  • urinating often
  • having blurry vision
  • being susceptible to infections
  • feeling thirsty or dehydrated
  • feeling a bit dizzy.

However, if left undiagnosed and untreated, high blood sugar can lead to diabetes and long-term complications including:

How to get tested

Most tests require blood samples.

There are various tests your doctor may perform if you have symptoms of high or low blood sugar, including a random blood sugar test, a fasting blood sugar test or an oral glucose tolerance test.

The most common test for diagnosis of diabetes is the fasting blood glucose test, where your blood glucose levels are checked after fasting for between 12 and 14 hours.  Glucose tolerance tests are usually given when your results from the fasting blood glucose test are borderline.

During a glucose tolerance test a high glucose drink is given and blood samples are taken regularly over the next 2 hours to check your blood glucose levels. Depending on the results, your doctor is able to determine if you have diabetes, or are at risk of developing diabetes in the future.

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