Appachan checks his sugar once a month and proudly says it is “always normal”. But a single sugar reading only shows what was happening on one particular morning. Diabetes is a long-term condition, so doctors often want a test that shows the bigger picture.
What fasting blood sugar shows
Fasting blood sugar measures the glucose in your blood after an overnight fast. It is quick and useful, but it can change from day to day depending on what you ate the night before, how you slept, stress and illness.
As a general guide, a fasting value below 100 mg/dL is considered normal, 100 to 125 mg/dL suggests prediabetes, and 126 mg/dL or above on repeated testing suggests diabetes.
What HbA1c shows
HbA1c measures how much sugar has attached to haemoglobin in your red blood cells. Because these cells live for a few months, HbA1c reflects your average blood sugar over roughly the last 2 to 3 months. It does not need fasting.
As a general guide, HbA1c below 5.7% is considered normal, 5.7% to 6.4% suggests prediabetes, and 6.5% or above suggests diabetes.
Which one is better?
Neither replaces the other. Fasting sugar tells you about today; HbA1c tells you about the last few months. Doctors commonly use both together, especially when diagnosing diabetes or checking how well treatment is working.
HbA1c may be less reliable in some situations, such as anaemia, certain haemoglobin variants, recent blood loss or pregnancy. Your doctor will decide which test suits you.
Who should get checked?
Anyone above 30 to 35 years, and anyone with a family history of diabetes, high blood pressure, excess weight around the waist, or a history of diabetes in pregnancy, should talk to their doctor about regular sugar screening. Prediabetes found early can often be managed with diet and activity.
Need a test done? Medlab Diagnostics, Pearl Towers, Choondi offers home sample collection and online reports. Book on WhatsApp or call us, and our team will guide you on preparation before the visit.
This article is for general awareness only. Please follow your doctor’s advice for your own health condition.