Diabetes Diagnosis

Diabetes is characterized by abnormally elevated blood glucose levels over a period of time. Insulin is either produced in too low amount (Type One Diabetes) or not used properly (Type Two Diabetes). Insulin is the principle hormone that helps the cells absorb glucose. Since the amount is a lot higher than normal, it's possible to take various tests that detect the difference.

One of the more standard tests is called a 'Fasting Plasma Glucose' (FPG) test. The patient doesn’t eat for at least eight hours (usually no consuming anything after midnight). The test is administered by drawing blood and measuring the results. A normal fasting glucose level will be lower than about 99 mg/dL.

Blood glucose levels between 100-125 mg/dL are good indication of a condition doctor’s name 'pre-diabetes'.  In this case, the person doesn't have diabetes but is very likely to develop it within a few years, unless the proper management of glucose levels are controlled by diet, exercise and possibly medication too.

A level of 126 mg/dL or higher is a very strong indicator of full blown diabetes. When it's seen doctors will typically recommend other tests to help confirm the patient is diabetic. One of the more common test is called an 'Oral Glucose Tolerance Test' (OGTT).

The glucose levels are then measured, then the test is repeated at intervals, usually two hours later, then three, then four. Sometimes the test interval is 30 min, 1 hour, 2 hours and so on.

A 2-hour glucose level of 139 mg/dL or below is considered normal. Insulin is released by the body in reaction to the high glucose and the cells take it up. But when the number is still 140-199 mg/dL two hours later, this is an indication that inadequate insulin is released or its normal action is being hindered. That suggests pre-diabetes. When the number is 200 mg/dL or higher, diabetes is indicated.

In the latter case, physicians will often recommend repeating the test at a later date to confirm the diagnosis. Many things can temporarily alter the body's blood glucose levels and its ability to regulate them. For example, taking steroids significantly alters blood glucose levels, as do certain diuretics. Pregnancy is one common example of a condition affecting glucose levels.

Another type of diabetes, one that occurs in about 3% of pregnancies (usually during 24-28 weeks gestation), is known as gestational diabetes. The OGTT is used to detect that as well. The test will be administered four times and the blood glucose level measured at each instance.

Another test commonly used is called the 'Random Plasma Glucose' (RPG) test. In this case a blood test is done without fasting. When the level is 200 mg/dL or higher it can indicate the presence of diabetes. Common symptoms are taken into account as well, such as unusually frequent urination, abnormal continued thirst even after drinking water and others.

No single diabetes diagnosis test conclusively proves that a person is diabetic. Since the condition is potentially serious, though often managed with minimal lifestyle interruption, a battery of tests should be used before reaching a confirmed diagnosis.