You should get tested for diabetes IMMEDIATELY if:
1. You have symptoms of diabetes (increased thirst, increased urination, lethargy, or unintentional weight loss), or
2. You are diagnosed with any complication of diabetes, or
3. You are pregnant
You should get tested EVERY YEAR if:
1. You were previously diagnosed with pre-diabetes
You should get tested EVERY 3 YEARS if:
1. You are more than 35 years old, or
2. You were previously diagnosed with gestational diabetes, or
3. You are living with HIV
In the absence of the above, you should get tested EVERY 3 YEARS if you have BMI > 23 kg/m2, or waist circumference more than 80cm (women) or 90cm (men) with:
1. An existing cardiovascular disease, or
2. A family member with diabetes, or
3. High blood pressure or high cholesterol, or
4. A birth weight of > 4kg, or
5. A history of maternal diabetes during pregnancy, or
6. Sedentary and inactive lifestyle, or
7. Existing hormonal disorders known to cause diabetes, or
8. Concomitant medications known to cause diabetes
In summary, you should get tested for diabetes if you are 35 years old or older, even in the absence of other risk factors. In the presence of risk factors for diabetes, testing should start even earlier.
Newer diabetes guidelines have recommended that testing for diabetes be made simpler and more convenient for patients. In general, you do not necessarily need to fast overnight or undergo an oral glucose tolerance test (OGTT) to diagnose diabetes. Your doctor can make a diagnosis by testing your random plasma glucose and HbA1c levels. If these results are non-conclusive, he or she may request you to repeat the test, perform a fasting plasma glucose test, or arrange an OGTT.
In some people whom HbA1c test may not be reliable (e.g. pregnancy or anemia), OGTT may still be needed to diagnose diabetes.