Over the years, diabetes has slowly become a major public health problem. Over twenty million people in the U.S. have diabetes according to the According to the juvenile diabetes association / foundation – most of them with type 2 diabetes. With the federal government and insurance companies facing increasing medical costs of treating diabetes and its associated problems, there is a great incentive to begin identifying those at risk for diabetes before they actually develop this chronic disease.
One way of determining this is with different kinds of diabetes pre-screening tests. Diabetes is a metabolic disorder in which a person has excess sugar in the blood. You can’t perform testing, however, by merely drawing blood and measuring the glucose levels. This is because a meaningful percentage of the populace has normal blood glucose levels during the day but elevated glucose levels as they eat throughout the day. Any valid test for diabetes has to take this into account.
There are three main tests for diabetes used by medical care practitioners. They all basically measure how fast and efficiently your body is able to clear glucose from your blood stream. A test showing results of relatively high glucose levels is a good indication that you have glucose intolerance, pre-diabetes, or diabetes. The three tests are:
1) Casual or random plasma glucose test – the patient can be tested at any point in the day. According to the American Diabetes Association, a test showing a casual plasma glucose concentration of 200 milligrams or more per deciliter (mg/dl) , indicates that the person can be diagnosed with diabetes.
2) Fasting plasma glucose (FPG) testing – sometimes referred to as the fasting blood sugar test because the patient has to fast before the test is administered. Fasting, in this context, means that the patient has not consumed food or drink, other than water, for at least eight hours prior to the test. It’s probably most convenient when done first thing in the morning after a night’s sleep. The test measures blood sugar levels. The normal glucose level after fasting is approximately 100 mg/dl. A diagnosis of diabetes can be made if the glucose concentration is 126 mg/dl or more. Monitoring of the blood glucose measurements persists throughout the day. Because this test is relatively inexpensive, it is a popular one with insurance companies and health care providers. This is also a standard test given to check for pre-diabetes.
3) Oral Glucose Tolerance Test (OGTT) – The best and most comprehensive of the tests. It is more sensitive than the FPG test and can test for impaired glucose intolerance which the other two cannot. It’s also the most expensive, making it the least popular with insurance companies and health providers. The test is performed two hours after orally taking 75 grams of glucose. A diagnosis of diabetes can be made if the blood glucose results show 200 mg/dl or greater.
It is possible that a test, for any number of reasons, can give a false positive and indicate that a person has diabetes when, in fact he doesn’t. This is why a diagnosis is not usually rendered until the results are confirmed with a repeat test.