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Standard Diagnoses For
Diabetes
Diabetes is characterized by abnormally elevated blood glucose
levels over a period of time. Insulin is either produced in too
low amount (Type 1) or not used properly (Type 2). Insulin is
the principle hormone that helps the cells take up glucose.
Since the amount is higher than normal, it's possible to take
different tests that detect them.
One of the standard tests is called a 'Fasting Plasma Glucose'
(FPG) test. The patient foregos eating for at least 8 hours
(usually nothing 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.
Levels between 100-125 mg/dL are an indication of a condition
professionals call 'pre-diabetes'. In this case, the person
doesn't have diabetes but is very likely to develop it within a
few years unless management of glucose levels is undertaken by
diet, exercise and possibly medication.
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 aid in confirming the diagnosis. One
of those is called an 'Oral Glucose Tolerance Test' (OGTT).
A patient who has fasted drinks a high glucose liquid (75
grams, not tasty but not harmful) and blood is drawn to test.
The glucose levels are 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 test conclusively proves that a person has diabetes.
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.
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