Blood glucose, often called blood sugar, is a measure of the amount of glucose circulating in the bloodstream. Glucose is derived from the food we eat, particularly carbohydrates, and serves as the primary source of energy for the body’s cells and organs. Monitoring this level is important because the body tightly regulates glucose concentration within a narrow range to maintain metabolic function. When blood glucose levels are consistently elevated over time, it can lead to health complications affecting the nerves, kidneys, and heart. In the United States, glucose levels are typically measured in milligrams per deciliter (mg/dL).
Interpreting Glucose Levels: Fasting vs. Non-Fasting
The meaning of a 115 mg/dL reading depends on whether the test was performed after fasting or if it was a casual, non-fasting measurement. A fasting plasma glucose (FPG) test requires abstaining from food or drink, other than water, for at least eight hours. Fasting results are categorized into three ranges based on established guidelines.
A reading below 100 mg/dL is considered normal for fasting blood glucose. A result of 126 mg/dL or higher, when confirmed by a second test, is used to diagnose diabetes. The range between these two points signifies an elevated risk level.
A fasting glucose level of 115 mg/dL falls into the category known as Impaired Fasting Glucose (IFG), or prediabetes (100 mg/dL to 125 mg/dL). This reading indicates the body is having difficulty processing glucose efficiently, though it is not yet at a diabetic level.
If the 115 mg/dL reading was taken randomly, without an overnight fast, the interpretation changes significantly. A non-fasting or casual glucose level under 140 mg/dL is generally considered a normal result. A fasting 115 mg/dL specifically serves as a warning sign for potential future health issues.
The Role of Confirmatory Testing
A single elevated blood glucose reading, such as a fasting 115 mg/dL, is not sufficient for a formal diagnosis of prediabetes or diabetes. Healthcare providers rely on specific confirmatory tests to establish long-term glucose control. These tests measure glucose levels over a broader time frame or challenge the body’s ability to manage a glucose load.
The Hemoglobin A1C (HbA1c) provides an average of blood sugar levels over the preceding two to three months. This test measures the percentage of hemoglobin proteins in the blood that have glucose attached. A normal A1C result is below 5.7%, while 5.7% to 6.4% indicates prediabetes. A diagnosis of diabetes is made when the A1C level is 6.5% or higher.
The Oral Glucose Tolerance Test (OGTT) is a second way to confirm glucose status, though it is used less frequently than the A1C. For this test, a patient fasts overnight, drinks a glucose-rich solution, and has their blood drawn two hours later. This shows how effectively the body cleared the sugar from the bloodstream. A two-hour result between 140 mg/dL and 199 mg/dL is consistent with prediabetes, while 200 mg/dL or greater suggests diabetes.
Actionable Steps to Manage Borderline Glucose
A borderline reading like 115 mg/dL offers an opportunity to normalize blood sugar levels and prevent the progression to type 2 diabetes. Lifestyle adjustments focusing on diet and physical activity are effective in reversing prediabetes. Losing a modest amount of weight is impactful; studies show that a loss of 5% to 7% of body weight can reduce the risk of developing diabetes by nearly 60%.
Dietary Changes
Dietary modifications should focus on improving the quality of carbohydrates consumed. This involves reducing the intake of refined carbohydrates and added sugars, which cause rapid spikes in blood glucose. Focus on incorporating fiber-rich foods, such as nonstarchy vegetables, whole grains, and legumes, which slow down sugar absorption and stabilize glucose levels.
Physical Activity
Consistent physical activity enhances the body’s sensitivity to insulin, allowing cells to absorb glucose more efficiently. Aim for at least 150 minutes of moderate-intensity aerobic exercise each week, such as brisk walking. These sessions help muscles utilize excess sugar circulating in the blood.
Maintain regular follow-up with a healthcare provider to monitor these efforts. Regular retesting, typically on an annual basis, ensures that glucose levels are trending back toward the normal range. Working with a physician allows for personalized guidance and the establishment of reasonable goals.