Blood Sugar Levels What You Need to Know

Blood sugar, or blood glucose, refers to the amount of glucose present in the bloodstream. The commonly used measure in clinical settings is serum glucose, which is determined through a blood sample taken from a vein. Normal blood glucose levels vary depending on whether the measurement is taken while fasting or after a meal.

Fasting Blood Sugar

Normal fasting blood glucose typically ranges between 3.9 and 6.1 mmol/L. For an accurate reading, individuals must refrain from eating or drinking for at least 8 hours before the test. After the test, it is important to apply pressure to the puncture site for 3–5 minutes to prevent bleeding. If fasting blood sugar levels fall between 6.1 and 7.0 mmol/L, this is classified as impaired fasting glucose. A level above 7.0 mmol/L may indicate diabetes. Low fasting glucose can occur due to various reasons including physiological changes, excessive insulin production, or liver-related hypoglycemia.

Post-Meal Blood Sugar

Blood glucose levels after eating vary depending on the time elapsed since the meal. One hour after eating, blood sugar should be below 11.1 mmol/L, and after two hours, it should return to a range between 3.9 and 7.8 mmol/L. For a diabetes diagnosis, an oral glucose tolerance test (OGTT) is often used. If the 2-hour post-meal glucose level is between 7.8 and 11.1 mmol/L, this is referred to as impaired glucose tolerance. A level exceeding 11.1 mmol/L strongly suggests diabetes. If elevated blood sugar is detected during a single test, it is recommended to repeat the test on another day to rule out temporary influences such as diet.

Understanding Prediabetes

Impaired fasting glucose and impaired glucose tolerance are both indicators of prediabetes, a condition that places individuals at a higher risk of developing type 2 diabetes. Those with prediabetes should consider making lifestyle changes, such as improving diet, increasing physical activity, and maintaining a healthy weight. Regular blood sugar monitoring is also essential, and in some cases, further testing like the glucose tolerance test may be necessary to determine if diabetes has developed.