Published: 25 Jun 2024

Reference Range and Reference Interval

The reference range, also known as the reference interval, encompasses the normal variations in a measurement or value observed in healthy individuals. It serves as a benchmark for healthcare providers to interpret patient test results.

Standard and Optimal Ranges

While the reference range and optimal levels may overlap, they can differ significantly, particularly for vitamins and blood lipids. Standard ranges reflect the most common values within a population, while optimal ranges represent values associated with optimal health or minimal disease risk.

Reference Range Origin

Reference ranges are typically established based on the distribution of values within a representative sample of the population. The usual reference range includes the values that 95% of healthy individuals fall within.

Terminology

The term "reference range" or "reference values" is now preferred over "normal range" due to potential misinterpretations. Reference values are often used interchangeably with reference range.

Interpretation of Results

Test results must be interpreted in context, considering individual factors such as age, activity level, and medical history. A result that falls outside the reference range does not necessarily indicate an abnormality. For example, a resting heart rate of 55 beats per minute may be normal for an athlete, while a rate of 120 beats per minute may be normal during exercise.