Learn what your blood sugar numbers mean — fasting, after meals, and how they relate to diabetes diagnosis and management.
Blood glucose (blood sugar) is the main sugar found in your blood. It comes from the food you eat and is your body's primary source of energy.
Your body regulates blood glucose with insulin, a hormone made by your pancreas. Insulin helps glucose move from your blood into your cells for energy. When this system doesn't work properly, blood sugar levels rise — this is what happens in diabetes.
Blood glucose is measured in mg/dL (milligrams per deciliter) in the US, or mmol/L in most other countries. The timing of the test matters — fasting levels and post-meal levels have different normal ranges.
After 8+ hours without eating
Healthy fasting glucose
Impaired fasting glucose
Diabetes range (if confirmed on two tests)
2 hours after eating
2 hours after eating
Impaired glucose tolerance
Diabetes range
| Blood Glucose | A1C | |
|---|---|---|
| Measures | Blood sugar right now | Average over 2-3 months |
| Fasting needed? | Yes (for fasting test) | No |
| Best for | Daily monitoring, diagnosis | Long-term control, trends |
| Home testing? | Yes (glucometer) | Usually lab only |
Both tests are important. Glucose shows daily patterns; A1C shows the big picture. Track both for complete diabetes management.
Upload lab reports and log home readings. See your glucose trends and know if your treatment is working.