Should your doctor feel that you might have diabetes, she will order a fasting blood glucose test for you in order to get a better idea of how your body deals with glucose. The American Diabetes Association recommends that you have the test done on two separate occasions so that you get an accurate diagnosis. This test is used for both diagnosis and monitoring of diabetes.
Function
Those who have certain symptoms need to have a fasting blood glucose test. According to the MedLine Plus website, this test is commonly ordered when a patient has fainting spells, has a seizure for the first time or has odd changes in behavior, as well as when a patient shows signs of diabetes. Symptoms of high blood sugar, or hyperglycemia, include increased urination or thirst, slow wound healing, blurred vision or fatigue, while symptoms of low blood sugar include trembling, hunger, anxiety, blurred vision, sweating or confusion, according to Lab Tests Online.
Process
For a fasting blood glucose test, your doctor will tell you to avoid eating for at least six to ten hours before the test. They usually schedule these tests in the morning to make this easier. With adults, the health professional will insert a needle in a vein in the inside of the elbow or on the back of the hand and draw blood into a vial. With children, they will sometimes use a pipette, according to MedLine Plus. Sometimes the doctor will also order a glucose load test. You will be asked to drink a high-glucose beverage and then get blood drawn after one and three or five hours, so the doctor can see how well your body handles the glucose.
Risks
The risks of the fasting blood glucose test are similar to those you would have with any other blood test, and relatively rare. These include infection, feeling lightheaded, blood accumulating under the skin, or bruising, and excessive bleeding, according to Medline Plus. It may be harder to draw blood from some people, resulting in multiple needle sticks rather than just one.
Other Conditions
Although diabetes is the main reason for this blood test, there are other conditions that could result in either high or low blood sugar, according to Lab Tests Online, so abnormal results warrant further testing. Those with low blood sugar might have hypothyroidism, adrenal insufficiency, extensive liver disease, hypopituitarism or insulinomia, or might just have had too little to eat or taken too much insulin. High levels of blood sugar can also mean pancreatic cancer, hyperthyroidism, pancreatitis, prediabetes, Cushing syndrome, acromegaly, chronic renal failure, acute stress, glucoganoma or pheochromacytoma.
Considerations
Doctors consider anything from 70 to 99 mg/dL to be normal fasting blood glucose test results, according to Lab Tests Online. However, those with abnormal results should know that there are various medications that can affect the results one way or the other, according to Medline Plus. This means it is important to discuss with your doctor any medications you are using, so they can be taken into account.
