Colorectal Cancer Screening: Essential Tests and Guidelines

Hemoglobin A1c, commonly known as HbA1c or glycated hemoglobin, is a blood test that provides important information about average blood sugar levels over the past two to three months. This test measures the percentage of hemoglobin proteins in red blood cells that have glucose attached to them. Since red blood cells live for approximately three months, the HbA1c test reflects the average amount of sugar in the bloodstream during that period. Unlike daily blood glucose tests that show sugar levels at a single moment in time, HbA1c gives healthcare providers a broader picture of how well blood sugar has been controlled over an extended period.

The HbA1c test is primarily used to diagnose diabetes and prediabetes, and to monitor how well people with diabetes are managing their condition. For diagnosis, an HbA1c level below 5.7 percent is considered normal. A result between 5.7 and 6.4 percent indicates prediabetes, meaning blood sugar levels are higher than normal but not yet high enough to be classified as diabetes. An HbA1c level of 6.5 percent or higher on two separate tests indicates diabetes. For people already diagnosed with diabetes, the test helps determine whether treatment plans are working effectively and whether adjustments to medication, diet, or lifestyle are needed.

The test is performed using a simple blood sample, which can be taken at any time of day without requiring fasting. This convenience makes it easier for patients compared to other glucose tests that require specific preparation. The blood sample is sent to a laboratory where specialized equipment measures the percentage of glycated hemoglobin. Results are typically available within a few days, though some medical facilities offer point-of-care testing that provides results during the same visit.

For individuals with diabetes, target HbA1c levels are generally set at less than 7 percent, though specific goals may vary based on individual circumstances such as age, overall health, and risk of complications. Higher HbA1c levels indicate poorer blood sugar control and increased risk of diabetes-related complications affecting the eyes, kidneys, nerves, and cardiovascular system. Regular HbA1c testing, typically every three to six months for people with diabetes, helps track progress and guides treatment decisions to prevent or delay these complications.