Diagnostic Tests for Type 2 diabetes
Diagnostic Test list for Type 2 diabetes: The list of diagnostic tests mentioned in various sources as used in the diagnosis of Type 2 diabetes includes:
- Urine sugar test
- Blood glucose test
- Fasting plasma glucose (FPG)
- Oral glucose tolerance test (OGTT)
- See also tests for diabetes
Tests and diagnosis discussion for Type 2 diabetes: If you are 45 years old or older, you need to get tested for diabetes, even if you do not have any of the risk factors listed below. If you are younger than 45 and have one or more risk factors, you should also get tested. Ask your doctor for a fasting blood glucose test. The results of this blood test will tell your doctor how much glucose is in your blood. Your doctor may ask you to have the test twice.
Even if your blood glucose level is normal and you have no risk factors, if you are over 45, you may need to remind your doctor to check your blood glucose again in 3 years. If you have at least one of the risk factors below, have your blood checked more frequently.1
A Lower Number To Diagnose Diabetes The expert committee also recommended a lower fasting plasma glucose (FPG) value to diagnose diabetes. The new FPG value is 126 milligrams per deciliter (mg/dL) or greater, rather than 140 mg/dL or greater. This recommendation was based on a review of the results of more than 15 years of research. This research showed that a fasting blood glucose of 126 mg/dL or greater is associated with an increased risk of diabetes complications affecting the eyes, nerves, and kidneys. When diagnosis was based on a blood glucose value of 140 mg/dL or greater, these complications often developed before the diagnosis of diabetes. The experts believe that earlier diagnosis and treatment can prevent or delay the costly and burdensome complications of diabetes.
The prior criteria for diagnosing diabetes relied heavily on performing an oral glucose tolerance test (OGTT). In this test, the person must come in fasting, drink a glucose syrup, and have a blood sample taken 2 hours later. This complicated procedure made detection and diagnosis of diabetes a difficult and cumbersome process, and the expert committee recommended that it be eliminated from clinical use. The change to using fasting plasma glucose for determining the presence of diabetes will make detection and diagnosis of diabetes more routine. The fasting value can be easily obtained during routine physician visits, in clinics at the place of employment, and other situations. Currently, about 5 to 6 million adults in the United States have diabetes but do not know it. The simpler testing method of measuring fasting glucose should help identify these people so they can benefit from treatment sooner.2
The committee states that diabetes can be detected by any of three positive tests. To confirm the diagnosis, there must be a second positive test on a different day.
A casual plasma glucose level (taken at any time of day) of 200 mg/dL or greater when the symptoms of diabetes are present.
A fasting plasma glucose value of 126 mg/dL or greater.
An OGTT value in the blood of 200 mg/dL or greater measured at the 2-hour interval.
The new diagnostic criteria for diabetes include the following changes:
- The routine diagnostic test for diabetes is now a fasting plasma
glucose test rather than the previously recommended oral glucose
tolerance test. (However, in certain clinical circumstances, physicians
may still choose to perform the oral glucose tolerance test.)
- A confirmed** fasting plasma glucose value of greater than or equal
to 126 milligrams/deciliter (mg/dL) indicates a diagnosis of diabetes.
Previously, a value of greater than or equal to 140 mg/dL had been
required for diagnosis.
- In the presence of symptoms of diabetes, a confirmed** nonfasting
plasma glucose value of greater than or equal to 200 mg/dL indicates a
diagnosis of diabetes.
- When a doctor chooses to perform an oral glucose tolerance test (by administering 75 grams of anhydrous glucose dissolved in water, in accordance with World Health Organization standards, and then measuring the plasma glucose concentration 2 hours later), a confirmed** glucose value of greater than or equal to 200 mg/dL indicates a diagnosis of diabetes.
*For further information about the new diagnostic
criteria for diabetes, please see the "Report of the Expert Committee on
the Diagnosis and Classification of Diabetes Mellitus," in the References.
**Except in certain specified circumstances, abnormal tests must be
confirmed by repeat testing on another day.
**Except in certain specified circumstances, abnormal tests must be confirmed by repeat testing on another day.3
One other number to know is the result of a blood test your doctor does called hemoglobin A-1-c (HE-muh-glow-bin A-1-C) or glycated hemoglobin (GLY-kay-ted HE-muh-glow-bin). It shows your blood glucose control during the past 2 to 3 months. For most people, a good hemoglobin A-1-c is 7 percent. 4
Diagnosis of Type 2 diabetes: medical news summaries: The following medical news items are relevant to diagnosis of Type 2 diabetes:
- Blood protein concentration may determine heart disease risk
- Uncontrolled diabetes can have serious consequences
1. excerpt from Am I at Risk for Type 2 Diabetes: NIDDK
2. excerpt from Diabetes Diagnosis: NIDDK
3. excerpt from Diabetes Statistics in the United States: NIDDK
4. excerpt from Medicines for People With Diabetes: NIDDK
Last revision: April 10, 2003
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