How is Diabetes diagnosed?
The following tests are used for the diagnosis of diabetes:
A Fasting Plasma Glucose Test: This test measures your blood glucose after you have gone at least 8 hours without eating. This test is used to detect diabetes or prediabetes. The FPG is the preferred test for diagnosing diabetes and is most reliable when done in the morning. A fasting blood glucose of 100-70 is normal. If your fasting glucose level is 100 to 125 mg/dL, you have a form of prediabetes called impaired fasting glucose (IFG), meaning that you are more likely to develop type 2 diabetes but do not have it yet. A level of 126 mg/dL or above, confirmed by repeating the test on another day, means that you have diabetes. An Oral Glucose Tolerance Test: This test measures your blood sugar after you have gone at least eight hours without eating and two hours after you drink a glucose-containing beverage. This test can be used to diagnose diabetes or prediabetes. The OGTT requires you to fast for at least eight hours before the test. Your plasma glucose is measured immediately before and two hours after you drink a liquid containing 75 grams of glucose dissolved in water. If your blood sugar level is 139 and below then this is normal. If your blood sugar level is between 140 and 199 mg/dL 2 hours after drinking the liquid, you have a form of prediabetes called impaired glucose tolerance or IGT, meaning that you are more likely to develop type 2 diabetes but do not have it yet. A two-hour glucose level of 200 mg/dL or above, confirmed by repeating the test on another day, means that you have diabetes. Gestational diabetes is also diagnosed based on plasma glucose values measured during the OGTT. Blood sugar levels are checked four times during the test. If your blood sugar levels are above normal at least twice during the test, you have gestational diabetes. A Random Plasma Glucose Test: This is where your blood sugar is checked without regard to when you ate your last meal. This test, along with an assessment of symptoms, is used to diagnose diabetes, but not prediabetes. A random blood glucose level of 200 mg/dL or more, plus presence of the following symptoms, can mean that you have diabetes:
Other symptoms include fatigue, blurred vision, increased hunger, and sores that do not heal. Your doctor will check your blood glucose level on another day using the FPG or the OGTT to confirm the diagnosis of diabetes. Hemoglobin A1c: Is a newer guideline screening tool for prediabetes or diabetes. The test is normally used to measure blood glucose control in diabetes patients over several months). An HbA1c of 5.7% to 6.4% is consistent with prediabetes and marks a time when it can be reversed by lifestyle changes. An HbA1c of 6.5% or higher is consistent with diabetes. |