Diabetes Tests

Diabetes tests are used to diagnose diabetes mellitus, which is determined by the level of glucose in the blood. These tests normally involve analysis of a small sample of blood and, in some cases, urine.

Usually, if someone displays the classic symptoms of diabetes, a physician will normally test the level of glucose in the blood and urine, to determine or confirm whether the symptoms are indeed a manifestation of diabetes mellitus.

Tests for diabetes are also usually performed by a physician during routine physical examination, even though the individual may not display any noticeable signs or symptoms of diabetes.

It is possible for some persons to have elevated blood glucose levels but not high enough to be classified as diabetics. They may, however, be at risk of developing diabetes mellitus, unless steps are taken to minimize their risk. Such measures include improved diet, regular exercise and weight reduction (if necessary).

Normal Glucose Levels

Normal levels of blood glucose depend on whether measurement was done while the patient was fasting or done at any time without regard to meals. Fasting, in this case, means consuming no food at least eight hours prior to the test being done.

A fasting blood glucose level that is less than 110mg/dl is considered to be within normal range. When fasting blood glucose level is greater than 110mg/dl but less hand 126mg/dl, the patient is said to be in intermediate group. This means that their blood glucose level is not quite high enough to be classed as dibasic, but not low enough to be classed as normal.

When testing is done without regard to fasting, a blood glucose level of 140mg/dl or less is considered normal. If the glucose level ranges between 140 to 200mg/dl, the patient is considered to be within the intermediate group. Over 200mg/dl is normally classified as diabetic.

Note: Blood glucose is measured in milligrams per deciliter (mg/dl)

How is Blood Glucose Tested?

In former times, (nineteenth century) physicians actually tasted urine in order to determine its "sweetness" and to establish whether the patient was diabetic.

Thankfully, such methods are no longer used to diagnose diabetes mellitus. Diabetes tests are more focused on testing actual blood samples rather than urine. Testing the urine for glucose is not always reliable since the renal threshold for glucose varies from individual to individual. The urine threshold for glucose is the point above which the urine will contain sugar.

Usually testing blood glucose level is sufficient to diagnose diabetes mellitus. To confirm the diagnosis, however, the urine may also be tested for glucose and ketones. Ketones are toxic by-products, produced by improper metabolism of fats, caused by diabetes mellitus. This condition is known as Diabetic Ketoacidosis.

Additionally, a physician may perform an oral glucose tolerance test. With this test, the individual is required to drink a solution containing 75 grams of glucose, after which the blood glucose level is tested at various intervals (1/2 hour, 1 hour, 2 hours, 3 hours). If blood glucose level rises to 200 mg/dl or greater, for a period of two (2) hours or more, the patient is most likely diabetic.

A single round of diabetes tests is normally not sufficient to diagnose diabetes mellitus. Usually, a diagnosis is only confirmed with repeated test on a subsequent day.

Self-Monitoring Tests

If the results of diabetes tests confirm that a patient is diabetic, regular monitoring and testing of blood glucose levels are very important. This enables a patient to determine whether blood sugar levels are too high or too low, so that appropriate action can be taken.


Self-testing is easy. Patients only need a drop of blood and a glucometer to measure their blood glucose level. With advances in technology, patients can now use a wrist-watch-style meter that can detect blood sugar level through the skin.

Regular testing is important and should be done at least daily. Patients who take insulin should also test their blood glucose level either at lunch, dinner or bed time.

Early detection of diabetes mellitus offers the best opportunity for effective control and treatment. Diabetes tests should be performed when someone displays the classic symptoms of diabetes. Even when there are no noticeable symptoms, it is still a good idea to perform routine diabetes tests. This may help to detect the early stages of development of diabetes mellitus and allow for the implementation of lifestyle changes (such as adjustment of diet, exercise and weight control) that can help to minimize long term complication.