How Are Diabetes and Prediabetes Diagnosed?

The following tests are used to diagnose diabetes:

  A fasting blood glucose test measures your blood sugar when you haven't eaten for more than 8 hours. This test is used to detect diabetes or prediabetes. The oral glucose tolerance test measures blood glucose levels after drinking a glucose-containing beverage and not eating for at least 8 and 2 hours. This test can be used to diagnose diabetes or prediabetes. In a random plasma glucose test, your doctor will check your blood sugar level regardless of when your last meal was. This test is used to diagnose diabetes and evaluate symptoms, but not to diagnose prediabetes. The hemoglobin A1c (HbA1c) test can be done without fasting and can be used to diagnose or confirm prediabetes or diabetes. A

 A positive test result should be confirmed by repeating the fasting plasma glucose tolerance test or the oral glucose tolerance test on another day. When diagnosing diabetes for the first time, your doctor may recommend a zinc transporter 8 autoantibody test (ZnT8Ab). This blood test, along with other information and test results, can help determine if a person has type 1 diabetes. The purpose of the ZnT8Ab test is a rapid and accurate diagnosis that can lead to timely treatment.

 Fasting Plasma Glucose (FPG) Test

  FPG is most reliable when running in the morning. The results and significance are shown in Table 1. When the fasting blood sugar level is 100-125 mg/dL, there is a form of prediabetes called fasting glucose disorder (IFG). This means you're more likely to develop type 2 diabetes but don't have it yet. A reading of 126 mg/dL or higher, confirmed by repeating the test another day, means you have diabetes.

 Oral Glucose Tolerance Test (OGTT)

 Studies have shown that the OGTT is more sensitive than the FPG test for diagnosing prediabetes, but it is not suitable for use. The OGTT should be fasted at least 8 hours before the test. Plasma glucose is measured immediately before and 2 hours after drinking 75 grams of glucose liquid in water. The results and significance are shown in Table 2. If the blood sugar level is 140-199 mg/dl 2 hours after drinking the liquid, there is a form of impaired glucose tolerance or prediabetes called IGT. This means you are more likely to develop type 2 diabetes but do not. I still have it. A 2-hour blood glucose level of 200 mg/dL or higher is confirmed by repeating the test another day and means you have diabetes.

 Gestational diabetes is diagnosed using blood glucose levels measured during the OGTT. Blood sugar levels are checked four times during the test. If your blood sugar level is more than twice the normal level at the time of the test, you will have gestational diabetes. Table 3 shows the unusual results of oGTT for gestational diabetes.

Random plasma glucose test

 Random blood sugar levels above 200 mg/dL and the presence of the following symptoms may indicate diabetes.

•  increased urination
•  increased thirst
•  unexplained weight loss

 Other symptoms include fatigue, blurred vision, increased hunger, and non-healing sores. Your doctor will check your blood sugar with the FPG or OGTT another day to confirm your diabetes diagnosis.

 Recent guidelines use hemoglobin A1c as a screening tool or diagnostic test for prediabetes or diabetes (this test is often used to measure glycemic control in diabetics over several months). .. HbA1c from 5.7% to 6.4% is consistent with prediabetes, indicating when lifestyle changes can be reversed. HbA1c above 6.5% indicates diabetes.