Here are federal guides for when to get checked for diabetes:
People older than 35 should be tested for prediabetes or diabetes. If the first blood
sugar (glucose) test is normal, they should get tested again every 3 years.
People of any age should be tested every 3 years for prediabetes or diabetes if they
are overweight or obese (body mass index (BMI) of 25 or more or 23 or more in Asian
Americans) and have one or more risk factors. Risk factors include:
Have a mother, father, brother, or sister with diabetes
Are part of a high-risk ethnic group. This means African American, Hispanic, Asian,
Pacific Islander, Native Alaskan, or Native American.
Had heart and blood vessel disease in the past
Have blood pressure at 140/90 mm/Hg or higher. Or are taking medicine for high blood
Have blood fat levels that are not normal. For example, high-density lipoproteins
(HDL) of less than 35 mg/dL. Or triglycerides greater than 250 mg/dL.
Are not active
Had impaired glucose tolerance during a past test for diabetes
Are a woman with polycystic ovarian syndrome (PCOS)
Have been diagnosed with prediabetes
Have symptoms of diabetes. These include increased urination, increased thirst, increased
hunger, and unexplained weight loss.
A diagnosis of diabetes
Any of the following test results confirm a diabetes diagnosis:
A1C level of 6.5% or higher.
Fasting plasma glucose (FPG) level of 126 mg/dL or higher. Fasting means not eating
or drinking except water for at least 8 hours.
Casual plasma glucose level of 200 mg/dL or higher, with the symptoms of high blood
sugar (hyperglycemia) or hyperglycemic crisis. This level can be measured at any time
Oral glucose tolerance test (OGTT) level of 200 mg/dL or higher. For this test, you
fast for at least 8 hours. Then you drink a sweet liquid that has a certain amount
If you don't have symptoms of hyperglycemia, a diagnosis requires 2 abnormal tests
results from the same sample, or from 2 separate test samples. For example, an FPG
of less than 126 and an A1C of less than 6.5% would be needed to diagnose diabetes.
Some conditions can affect the accuracy of the A1C test. These include:
Sickle cell disease
Pregnancy (second and third trimesters and the postpartum period)
Glucose-6-phosphate dehydrogenase deficiency
Recent blood loss or blood transfusion
A diagnosis of gestational diabetes
Gestational diabetes is diabetes that starts during pregnancy. All women who are at
risk for type 2 diabetes should be tested for diabetes at their first prenatal visit.
This is done using the standard tests above. More tests to check for gestational diabetes
will be done later in pregnancy. Gestational diabetes may be diagnosed with one of
the methods below.
This is a 75-gram glucose tolerance test. For this test, you drink a sweet glucose
drink. Blood sugar levels are checked after you have fasted for at least 8 hours.
They are also checked 1 hour after the drink and 2 hours after the drink. This test
is done at 24 to 28 weeks' gestation in women who have not been diagnosed with diabetes
before. Gestational diabetes is diagnosed when you have any one of the following blood
Fasting: 92 mg/dL or higher
1 hour: 180 mg/dL or higher
2 hour: 153 mg/dL or higher
This test is also done at 24 to 28 weeks' gestation in women who have not been diagnosed
Step 1. A 50-gram glucose tolerance test with a blood sugar level check at 1 hour. If the
blood sugar at 1 hour is 130 to 140 mg/dL or higher, then go to step 2.
Step 2. A100-gram glucose tolerance test is done while you are fasting. Gestational diabetes
is diagnosed when you have at least 2 of the following blood sugar levels:
Fasting: 95 mg/dL or higher
1 hour: 180 mg/dL or higher
2 hour: 155 mg/dL or higher
3 hour: 140 mg/dL or higher
Talk with your healthcare provider about being screened for gestational diabetes.
Women who have been diagnosed with gestational diabetes should be tested for diabetes
at least every 3 years.