Types of blood sugar tests
There are three common blood sugar tests: Fasting Blood Sugar (FBS) — measured after 8–12 hours of no food; Postprandial Blood Sugar (PPBS or PP) — measured exactly 2 hours after a meal; Random Blood Sugar (RBS) — measured at any time without fasting. Each has different normal ranges. Most labs in India report in mg/dL.
Blood Sugar Normal Ranges
| Test Type | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| Fasting (FBS) | < 100 mg/dL | 100 – 125 mg/dL | ≥ 126 mg/dL |
| Post-meal 2hr (PPBS) | < 140 mg/dL | 140 – 199 mg/dL | ≥ 200 mg/dL |
| Random (RBS) | < 140 mg/dL | 140 – 199 mg/dL | ≥ 200 mg/dL (with symptoms) |
| HbA1c | < 5.7% | 5.7 – 6.4% | ≥ 6.5% |
What does HIGH fasting blood sugar mean?
HIGH Fasting sugar ≥ 126 mg/dL on two occasions — Diabetes
A fasting blood sugar of 126 mg/dL or above on two separate tests confirms diabetes. Common symptoms of diabetes: frequent urination (especially at night), excessive thirst, unexplained weight loss, blurred vision, fatigue, slow-healing wounds, frequent infections. India has the second-highest number of diabetics in the world — an estimated 101 million people. Type 2 diabetes is preventable with diet, exercise and weight management at the prediabetes stage.
What is Prediabetes?
BORDERLINE Fasting sugar 100–125 mg/dL — Prediabetes
Prediabetes means your blood sugar is higher than normal but not yet at diabetes levels. Without action, 15–30% of people with prediabetes develop Type 2 diabetes within 5 years. The good news: prediabetes is almost always reversible with lifestyle changes — losing 5–7% of body weight, exercising 150 minutes per week, and reducing refined carbohydrates. No medication is needed at this stage in most cases. Recheck every 6–12 months.
What does LOW blood sugar mean?
LOW Blood sugar below 70 mg/dL — Hypoglycaemia
Low blood sugar (hypoglycaemia) causes shakiness, sweating, dizziness, confusion, palpitations and hunger. In people on diabetes medication (insulin, sulfonylureas), hypoglycaemia is a common and potentially dangerous side effect. In people not on medication, persistent low blood sugar (especially fasting) needs investigation for insulinoma or other causes. Eat something with quick sugar (glucose tablets, fruit juice) to treat an episode immediately.
Questions to ask your doctor
- Is a single high reading enough to diagnose diabetes or do I need a repeat test?
- Should I also check HbA1c for a 3-month average?
- Do I need medication or can I manage this with diet changes?
- What blood sugar targets should I aim for?