Reference intervals are printed beside many lab results. This guide explains what they are for logistically and why your clinician still matters — it does not tell you whether your own numbers are normal.
What a reference interval is
It is a statistical band derived by a lab or assay manufacturer for a defined population and method. Another lab can use a different machine and show a different interval for the same analyte name.
Practical habits for families
- Compare new results to prior results from the same lab when possible.
- Ask your doctor when a “borderline” flag needs retesting versus watchful waiting.
- Do not change medications based on a single printout without medical review.