Blood Glucose

Blood glucose (blood sugar) is the amount of sugar in the blood. It's the main fuel for the body's cells — but both low and high levels cause problems. For Indians, where diabetes prevalence is high and onset is a decade earlier than in Europeans, knowing your numbers is one of the most useful things you can do.

The three common tests

• Fasting plasma glucose (FPG) — after 8 hours without food.
• 2-hour plasma glucose (OGTT) — 2 hours after a 75 g glucose drink.
• HbA1c — average of the last 2–3 months; no fasting needed.

What the numbers mean

• Normal — FPG < 100 mg/dL, 2-hr PP < 140 mg/dL, HbA1c < 5.7%.
• Prediabetes — FPG 100–125, 2-hr PP 140–199, HbA1c 5.7–6.4%.
• Diabetes — FPG ≥ 126 or 2-hr PP ≥ 200 or HbA1c ≥ 6.5% (confirm on two tests unless symptoms plus random glucose ≥ 200).
• Pregnancy — thresholds are lower; a separate oral glucose tolerance test between 24–28 weeks screens for gestational diabetes.

Who should be tested

• All Indian adults from age 30 — earlier than global guidelines, because Asian Indians develop diabetes at a lower BMI and younger age.
• Earlier if: BMI ≥ 23 + family history / high BP / PCOS / past gestational diabetes / fatty liver / sedentary lifestyle.
• If normal, repeat every 2–3 years; if prediabetic, yearly; if diabetic, as advised.
• Pregnancy: screen in the first trimester and again at 24–28 weeks.

Self-monitoring at home

• Home glucometers are cheap and reliable; a continuous glucose monitor (CGM) gives far richer information — useful for insulin users and during diagnosis/adjustment phases.
• Check timing, frequency, and targets with your doctor. More is not always better — testing fatigue and over-adjustment are real problems.
• Low blood sugar (hypoglycaemia) — shaky, sweaty, hungry, dizzy, confused. Treat with 15 g glucose / 3 tsp sugar in water / 3 candies; recheck in 15 minutes; eat a snack. If severe or unconscious, dial 112. See Hypoglycaemia.