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Healtheuniversity > English > Diabetes College > Treat Diabetes > What is Diabetes > Tests to Diagnose Diabetes

Tests to Diagnose Diabetes

There are different tests you could have to diagnose diabetes.

  • Random blood glucose test
  • Fasting blood glucose test
  • Oral glucose tolerance test
  • A1c test

There are different tests you could have to diagnose (find) diabetes. These tests are done with your routine blood work. There are 4 tests described below. All of these tests check your blood sugar level.

Note: The word "glucose" is used often when describing tests. Glucose is another term for sugar.

Random Blood Glucose Test

This test measures the sugar in your blood. It uses a sample of your blood.

For this test, it does not matter when you last ate or drank. The results show what your blood sugar is at the time you have blood taken. These results can be affected by when you last ate and what you had to eat and drink that day.

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Fasting Blood Glucose Test

This test measures the sugar in your blood. It uses a sample of blood.

For this test, you cannot eat or drink for at least 8 hours before the test. The results show your blood sugar level with no food or drink.

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Oral Glucose Tolerance Test

This test measures the sugar in your blood. It uses a sample of your blood.

For this test, you must drink a sugary liquid. The results show your blood sugar level after drinking a specific amount of sugar. This test is not done with your routine blood work and is specially ordered by your doctor.

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A1c Test

This test measures your blood sugar control over the last 3 months. This test uses a sample of your blood.

For this test, it does not matter when you last ate or drank. The test counts the number of blood cells with sugar. The results are shown in percent (%). This number can be changed into an average blood sugar.

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Last Reviewed: 10/16/2016