What is the fasting plasma glucose (FPG) level that indicates a diagnosis of Diabetes Mellitus?

A fasting plasma glucose (FPG) level greater than 126 mg/dL is an established diagnostic criterion for Diabetes Mellitus. This is based on the guidelines set forth by organizations such as the American Diabetes Association (ADA), which defines diabetes through specific threshold values for various glucose measurements.

The rationale behind using the FPG level of 126 mg/dL is that at this concentration, it indicates significant impairment in glucose regulation, meaning the body is either not producing enough insulin or is unable to utilize insulin effectively. This results in elevated blood sugar levels, which is characteristic of diabetes.

The FPG test is particularly useful because it measures blood glucose after at least eight hours of fasting, providing a clear snapshot of how well the body manages glucose in a non-stimulated state. Diagnosing diabetes at this threshold helps health care providers initiate appropriate management strategies sooner, thus preventing complications that can arise from prolonged elevated blood glucose levels.

In contrast, levels less than 100 mg/dL are considered normal, and levels between 100 mg/dL and 125 mg/dL are categorized as prediabetes, indicating a higher risk of developing diabetes in the future but not meeting the criteria for a definitive diagnosis. A level of 200 mg/dL or