The blood glucose test is done to check if your blood glucose levels are within the normal range, and is very often done in order to diagnose as well as monitor diabetes, and is the preferred test by most physicians because it is easy to do, convenient for patients, cheap and gives an accurate measure. This test is referred to by other names such as blood sugar test and fasting blood glucose test.

When your physician suspects that you might be having altered levels of blood glucose or if you complain to your doctor about symptoms such as increased thirst and hunger, unexplained weight loss, or the need to pass urine frequently, then your doctor might order this test.

Before you undergo this test, you will be asked to keep fasting, that is not eat or drink anything for a period of 8-10 hours. If there is any other specific preparations you have to make, then your healthcare provider will inform you about it.

During this, a Medical Lab Technician will draw out a small volume of blood, using a needle and syringe which is inserted into a vein in your arm. Once the necessary volume is collected, the sample is sent to the lab for analysis.

Since this test is a simple drawing of blood, you will not feel a lot of discomfort. You might experience a mild pain on inserting the needle, but you will not experience any uneasiness afterwards.

There is very little risk in undergoing a blood glucose test, because it is a simple blood drawing. Very rarely you might continue to have a mild pain or some swelling at the site where the needle was inserted, but these symptoms will more often than not resolve on their own within a couple of days.

A normal blood glucose level is considered anywhere between 70-100 mg/dL. When your fasting blood glucose levels are greater than 126 mg/dL on two separate occasions, then you are likely to be diagnosed with hyperglycemia. The commonest cause of hyperglycemia is diabetes, but other causes include, kidney disease, hyperthyroidism and pancreatitis. When your blood glucose level is less than 70 mg/dL, it is considered to be hypoglycemia, and the causes for this include, intake of too much insulin, diabetic medication, or skipping meals if you have already been diagnosed with diabetes, or conditions such as liver disease and hypothyroidism.

When you are undergoing a fasting blood glucose test, the time that you have been fasting plays a role in altering the blood glucose levels. Therefore make sure you have the blood drawn for testing between 8-10 hours of fasting and in not less or more time than that.

https://www.webmd.com/diabetes/type-2-diabetes-guide/diagnosing-type-2-diabetes#3 https://medlineplus.gov/lab-tests/blood-glucose-test/