How to read your lab results
Updated October 18, 2026
A lab report looks like a wall of numbers. It is easier than it looks. Almost every report has the same few columns.
The columns
| Column | What it means |
|---|---|
| Test or component | What was measured, such as Hemoglobin or Glucose. |
| Result or value | Your number, with its unit (mg/dL, g/dL and so on). |
| Reference range | The range the lab uses for most healthy people. Also called the normal range. |
| Flag | A letter such as H (high), L (low) or A (abnormal). Some labs mark critical values with C or HH or LL. |
What “normal” really means
A reference range is built from a large group of healthy people. By design, a small share of healthy people fall just outside it. So a result a little outside the range is common and is often not a problem. It is a reason to ask, not a reason to panic.
Ranges also differ between labs, and by age and sex. Go by the range printed on your own report, not one from the internet.
If a result is flagged
- Look at how far outside the range it is. A little over is very different from far over.
- Look at whether other related results are also off. Doctors read results together.
- Write down your questions and ask your doctor. Do not decide what it means on your own.
- If the report says critical, or you feel unwell, contact your doctor right away.
Fasting and timing
Some tests, like glucose and triglycerides, change with food. Medicines, supplements and even the time of day can change results too. Tell your doctor about these.
WillILive can do the reading for you. Add a photo or PDF of your report and we explain each result in plain words.
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