Since it can take time for patients to develop symptoms, early screenings of prediabetes (elevated blood sugar levels) and diabetes are important. Diabetes is the 7^th leading cause of death in the United States and can have complications that include heart disease and joint disorders.

Here are the four most common types of diabetes screenings:

1. A1C test
2. Fasting blood sugar test
3. Random blood sugar test
4. Glucose tolerance test

Learn more about how you can read your numbers for each test below.

1. A1C Test

The A1C test measures your average blood sugar levels over the last three months. It’s the most common blood test to diagnose both Type 1 and Type 2 diabetes, as well as for monitoring blood sugar levels for diabetics. For an A1C test, blood samples are drawn and results are usually available within 24 hours.

How to read your numbers: The normal range is below 5.7%. 5.7%-6.4% indicates prediabetes, while 6.5% and above indicates diabetes.

2. Fasting Blood Sugar Test

A fasting blood sugar test has these specific requirements:

• Overnight fasting – refraining from eating or drinking food or liquids besides water for at least eight hours.
• The blood sample must be taken after fasting, typically in the morning before breakfast.

How to read your numbers: The normal range is 70-100mg/dL. 100-126 mg/dL indicates prediabetes, while 126 mg/dL and above indicates diabetes.

3. Random Blood Sugar Test

A random blood sugar (RBS) test measures your blood sugar levels at the time of testing. This test doesn’t have to be done at a specific time of day, nor does it require fasting.

Random blood sugar tests can be performed as an outpatient procedure in a doctor’s office or diagnostic center. It involves collecting a blood sample, with results typically available on the same day. Patients can even choose to try a DIY version using a home kit with a lancet (a finger prick device) and glucometer. An RBS test can only test for diabetes, not prediabetes.

How to read your numbers: A blood sugar level of 200mg/dL and above indicates diabetes, especially if accompanied by the following symptoms of elevated blood sugar levels:

• Increased urination
• Increased thirst
• Weight loss
• Blurry vision

4. Glucose Tolerance Test

A glucose tolerance test measures how your body responds to sugar or glucose. While it’s commonly used as a screening test for Type 2 diabetes, a modified version is used to test for gestational diabetes — a kind of diabetes that occurs in pregnant women.

Like a fasting blood sugar test, taking a glucose tolerance test requires both fasting and a blood sample taken before breakfast. This is to measure your fasting blood glucose levels.

You’ll then be given eight ounces of a glucose solution. After two hours, another blood test will be performed to measure your blood glucose levels.

How to read your numbers: At two hours, the normal range is 140mg/dL and below. 140-199 mg/dL indicates prediabetes, while 200 mg/dL and above indicates diabetes.

According to the American Diabetes Association, adults who are 45 years of age and above should get Type 2 diabetes screenings every three years. Anyone considered overweight or obese should have earlier and more frequent screenings.

Talk to your doctor about whether you’re at risk for diabetes and if you should get your blood sugar levels tested. You should also discuss preventive measures and lifestyle changes.