How to read your blood test report
Key takeaways
- Every result has three parts: the value, the unit and the lab's reference range.
- A reference range describes most healthy people; being slightly outside it is not automatically a problem.
- Units differ between labs and countries — convert before comparing.
- For comparing reports over time, use the same lab and the same preparation.
What are the parts of a blood test result?
Each line shows the test name, your value, the unit it is measured in, and the reference range — the spread of values the lab expects in most healthy people. Many labs add a flag such as H (high) or L (low) when your value falls outside that range.
What does "reference range" really mean?
A reference range is usually built so that about 95% of healthy people fall inside it. That means some healthy people sit just outside it, and a value inside the range is not always "optimal" for your goals. Ranges also differ by lab, method, age and sex.
That is why a coach looks at patterns across markers and over time, and why flagged results that need medical attention go to a doctor.
How do I convert units?
Indian labs mostly use conventional units such as mg/dL and ng/mL, while many international sources use SI units such as mmol/L and nmol/L. Use a conversion factor before comparing numbers.
| Marker | Conversion |
|---|---|
| Vitamin D (25-OH) | ng/mL × 2.5 = nmol/L |
| Glucose | mg/dL ÷ 18 = mmol/L |
| Total, LDL and HDL cholesterol | mg/dL ÷ 38.67 = mmol/L |
| Triglycerides | mg/dL ÷ 88.57 = mmol/L |
What can make a result look wrong?
Not fasting when you should have, hard exercise in the previous day or two, dehydration, illness, some supplements and the time of day can all shift results. Iron-deficiency anaemia can also affect HbA1c. If a result surprises you, discuss a repeat test with your doctor.
- Fasting: glucose and triglycerides are affected by recent food.
- Hard training: can temporarily raise creatinine and muscle-related liver enzymes.
- Biotin supplements: can interfere with some tests, including certain thyroid tests.
How do I compare two reports?
Compare like with like: same lab if possible, same time of morning, same fasting, no hard workout the day before, and the same units. Then look at direction and size of change rather than single numbers.
The Fitfarmer app lays your markers out side by side after each retest, with each value marked optimal, borderline, low or high against the lab's range.
Questions
My value is flagged H but only slightly. Should I worry?
Not necessarily. Small deviations are common and can be influenced by preparation. Look at the whole report and ask a doctor, especially if the value is far outside the range or you have symptoms.
Why are my results different from another lab?
Labs use different machines, methods and reference ranges. For tracking progress, stick with one lab where you can.
Can Fitfarmer explain my report?
Coach Arun uses your report to shape training and food, and flags anything that needs medical attention for the partner doctor. Diagnosis and treatment are for your doctor.
Related: which tests to take · why retest after 8 weeks · the Fitfarmer panel