Blood sugar monitoring provides insights into glucose regulation over time. While daily readings offer immediate snapshots, the A1C test provides a broader, long-term perspective. This indicator is crucial for assessing risk and managing blood sugar conditions.
What is Glycated Hemoglobin
Glycated hemoglobin, commonly known as A1C, is a blood test reflecting your average blood sugar levels over the preceding two to three months. Glucose naturally attaches to hemoglobin, a protein found within red blood cells. Since red blood cells typically live for about three months, the A1C test captures the average amount of glucose attached to hemoglobin during their lifespan. The result is expressed as a percentage, indicating the proportion of hemoglobin with attached glucose. This measurement offers a stable, long-term view of glucose control, unlike daily finger-prick tests.
Relating Average Glucose to Glycated Hemoglobin
Understanding the connection between average daily glucose levels and A1C percentage is important for managing blood sugar. The A1C test result can be converted into an Estimated Average Glucose (eAG) value, presented in milligrams per deciliter (mg/dL), similar to typical home blood glucose meters. This conversion helps make the long-term A1C result more relatable to daily blood sugar readings.
The relationship between A1C and eAG is defined by the formula: eAG (mg/dL) = 28.7 × A1C – 46.7. An average glucose level of 148 mg/dL corresponds to an A1C of approximately 6.8%. While this conversion provides a useful estimate, individual variations can occur.
Understanding Your Glycated Hemoglobin Results
A1C results are categorized to indicate glucose status. A normal A1C level is below 5.7%. Levels between 5.7% and 6.4% indicate prediabetes, suggesting higher-than-normal blood sugar levels not yet high enough for a diabetes diagnosis. This range signals an increased risk for developing type 2 diabetes and cardiovascular disease. Individuals in this category are often advised to implement lifestyle changes to prevent progression.
An A1C of 6.5% or higher on two separate tests indicates diabetes. For those diagnosed with diabetes, the A1C test monitors treatment effectiveness. Healthcare providers often set personalized A1C goals, with a common target for many adults with diabetes being below 7%, although this can vary based on individual health factors.
Ensuring Accurate Glycated Hemoglobin Readings
Several factors can influence the accuracy of A1C test results, requiring careful interpretation by a healthcare professional. Certain medical conditions, such as anemia (including iron-deficiency anemia), kidney disease, and liver disease, can affect the lifespan of red blood cells or hemoglobin structure, potentially leading to falsely high or low A1C readings. Recent blood transfusions or significant blood loss can also impact results because they introduce new red blood cells into the system, altering the average glucose-hemoglobin binding. Some medications and certain hemoglobin variants may interfere with the test.
Discuss your full medical history and all current medications with your doctor before an A1C test. Healthcare providers recommend A1C testing at least twice a year for individuals managing diabetes who have stable blood sugar control, and more frequently, such as quarterly, if treatment plans have changed or if glucose targets are not being met. If initial screening results are normal, retesting frequency will depend on individual risk factors and age.