Hesperian Health Guides
Testing for Diabetes
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Blood sugar levels can be tested by a blood or urine test. Blood tests are more accurate.
Who should be tested?
A person should be tested for diabetes if she:
- has signs of diabetes.
- has a family member with diabetes.
- has a big waistline and is older than 40 years.
- has a history of high blood pressure.
- had a baby that was very large (over 4 kg or 9 lb).
- is young and has possible signs of Type 1 diabetes.
All types of diabetes can be detected by measuring blood sugar levels. The health worker may do more than one type of test to check for diabetes or may repeat a test. Tests can also be used to manage diabetes by helping you see how the results change in response to changes you make in your diet, activity, or medicine.
Blood tests measure if a person’s blood sugar levels are normal, if they are a little high, or if there is diabetes. If blood sugar levels are high but not yet as high as diabetes, a person can prevent getting diabetes by eating better and healthier foods, and exercising more.
There are 2 common blood tests for diabetes. One is called the Fasting Blood Sugar test and other one is the A1C test.
Fasting Blood Sugar (FBS or FPG) is the most common test. This test is done in the morning before the person eats anything. Some clinics test blood sugar levels with a glucometer, a tool that measures the sugar in a drop of blood taken from a fingertip. Or the clinic might take blood with a syringe and send it to a lab. The result of a Fasting Blood Sugar test depends on the measurement system used by your country. If measured in mmol/l (millimols per liter), the results will be a number between 4 and 20. If you have 6.9 mmol/l or more you could have diabetes. If your country measures in mg/dl (milligrams per deciliter), the result will be a number between 80 and 350. On this scale, people with 125 mg/dl or more could have diabetes.
|Some tests can be done with a drop of blood from a fingertip. For other tests, a vial of blood will be taken from your arm. A skilled health worker in a clinic can do this safely, causing only a little or no pain.|
The A1C test (glycosylated hemoglobin test, also called HbA1C or HgbA1C) gives an average of a person’s blood sugar level for the previous 3 months. A person does not have to be fasting to take this test. A clinic will take a blood sample with a syringe and send it to a lab. The result of an A1C blood test will be a percent (%) usually between 4% and 14%. If the result is close to 6.4%, or is higher, you may have diabetes. If the number is only a little lower than 6.4%, you will want to care for yourself in several ways and be tested again for diabetes in the future.
Urine tests can show that a person has diabetes. Urine test strips change color if there is sugar in the urine. Test as soon as the person urinates. A person does not need to be fasting for the test.
Urine tests will miss some cases of diabetes because sugar levels have to rise pretty high (10 mmol/l or 180 mg/dl) before sugar gets into the urine. So if the urine test does not show diabetes but there is another reason to think there could be diabetes, get a blood test.