Reference Range
Definition
The set of numbers forming the lower and upper limits of results considered normal. These ranges are derived from the test results of a large number of healthy people and can vary by age group or other factors.
Purpose
Helps you interpret what the number on your report means.
Why this glossary does not give a numeric range: Laboratories use different measurement methods and therefore set their own reference ranges. You cannot reliably compare your result with a range you find elsewhere, you need to look at the range on your own laboratory report. For the same reason, having repeat tests done at the same laboratory ensures that changes are tracked accurately.
Results
| Result type | Meaning |
|---|---|
| Negative / Normal | The finding being looked for was not detected |
| Positive / Abnormal | The substance, microbe, or gene being looked for was detected |
| Indeterminate | The result is not clear; the test is usually repeated |
Risks and Limitations
The word "normal" can be misleading. A result that falls within the range does not guarantee that your health is good, some people who truly have a disease will get results that are "normal". The opposite is also true: a result outside the range does not necessarily mean there is a problem; out-of-range values can also occur in healthy people.
Your doctor reaches a diagnosis by evaluating your result together with examination, medical history, and imaging.