Diabetes Diagnosis: Key Tests and Follow-Up for Seniors

Q: Diabetes Diagnosis: Key Tests and Follow-Up for Seniors

Hello： In response to your questions： 1. <br>In healthy individuals, postprandial blood glucose levels typically do not exceed 140 mg/dL and return to pre-meal levels within 2-3 hours. <br>The progression of type 2 diabetes is primarily characterized by the continuous deteriorati

Diagnosis of Diabetes Mellitus

Hello, Doctor: My mother is 78 years old and recently felt unwell, leading her to the emergency room where her fasting blood glucose was measured at 146.
She has no prior history of diabetes.
Subsequently, during a follow-up visit, the doctor only ordered postprandial blood glucose and hemoglobin A1c tests, stating that if both results are normal, she does not have diabetes.
Is this statement correct, or are there additional tests that should be performed?

rita, 30~39 year old female. Ask Date: 2010/08/18

Dr. Xiao Yongxun reply Internal Medicine

Hello: In response to your questions: 1.
In healthy individuals, postprandial blood glucose levels typically do not exceed 140 mg/dL and return to pre-meal levels within 2-3 hours.
The progression of type 2 diabetes is primarily characterized by the continuous deterioration of β-cell function, leading to decreased insulin secretion and a gradual increase in blood glucose levels.
At this stage, postprandial blood glucose levels begin to rise earlier than pre-meal levels.
2.
Glycated hemoglobin (HbA1c) has gradually become a mature criterion for diagnosing diabetes.
It is currently believed that an HbA1c level between 6% and 6.5% indicates prediabetes or impaired glucose tolerance, while an HbA1c level of 6.5% or higher is considered diabetes; this consensus was reached by the American Diabetes Association in 2009.
Clinically, many physicians have already noted these changes in diagnostic criteria.
3.
The above statements are supported by solid evidence in physiology, pathology, and clinical practice.
It is still advisable to discuss these matters in detail with your family physician.

Reply Date: 2010/08/18

More Info

When it comes to diagnosing diabetes, especially in older adults like your mother, it is essential to follow established medical guidelines to ensure accurate results and appropriate management. The American Diabetes Association (ADA) provides clear criteria for diagnosing diabetes, which include several key tests: fasting plasma glucose (FPG), oral glucose tolerance test (OGTT), and hemoglobin A1c (HbA1c).

In your mother's case, the fasting blood glucose level of 146 mg/dL is significant. According to the ADA, a fasting plasma glucose level of 126 mg/dL or higher indicates diabetes. Since your mother had a fasting blood glucose level above this threshold, it raises the possibility of diabetes. However, a single test result is not sufficient for a definitive diagnosis. The ADA recommends that a diagnosis of diabetes should be confirmed by repeating the test on a different day or by using an alternative method, such as the HbA1c test.

The HbA1c test provides an average of blood glucose levels over the past two to three months. An HbA1c level of 6.5% or higher is indicative of diabetes. If your mother's HbA1c result is below this threshold, it would suggest that she does not have diabetes, but it is important to consider the context of her fasting blood glucose result. If the HbA1c is normal (below 5.7%), it may indicate that her elevated fasting glucose was an isolated incident, possibly due to stress, illness, or other temporary factors.

In addition to these tests, the oral glucose tolerance test (OGTT) can also be performed. This test involves measuring blood glucose levels before and two hours after consuming a glucose-rich drink. If the two-hour blood glucose level is 200 mg/dL or higher, it indicates diabetes. This test is particularly useful in diagnosing cases where fasting glucose levels are borderline or when there are concerns about insulin resistance.

Given your mother's age and the elevated fasting blood glucose level, it is prudent for her to undergo further testing. The physician's approach of checking both postprandial (after meal) blood glucose and HbA1c is reasonable, but it is essential to ensure that the results are interpreted in conjunction with her fasting glucose level. If both the postprandial glucose and HbA1c are normal, it may suggest that she does not have diabetes. However, if any of these tests indicate diabetes, further evaluation and management will be necessary.

In summary, your mother's elevated fasting blood glucose level warrants further investigation. The physician's plan to check postprandial glucose and HbA1c is appropriate, but it is crucial to consider the fasting glucose result in the overall assessment. If there is any uncertainty or if the results indicate diabetes, it may be beneficial to consult an endocrinologist or a diabetes specialist for a comprehensive evaluation and management plan. Additionally, lifestyle modifications, including dietary changes and increased physical activity, should be encouraged to help manage blood glucose levels and reduce the risk of complications associated with diabetes.

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