Published: 25 Jun 2024

Reference Ranges and Optimal Levels

Definition:

A reference range or interval represents the natural variability of a laboratory value or measurement among healthy individuals.

Purpose:

Reference ranges provide a basis for healthcare professionals to interpret patient results and determine if they fall within expected levels.

Standard vs. Optimal Ranges:

* Standard Range: The range that includes approximately 95% of healthy individuals.
* Optimal (Health) Range: The range associated with optimal health outcomes or minimal disease risk.

Optimal Levels vs. Standard Range:

* Optimal levels are typically within the standard range but may be closer to the central tendency of the population.
* Optimal health ranges are based on levels believed to promote optimal health.

Reference Values vs. Normal Range:

The terms "reference values" and "reference range" are now preferred over "normal range" as they better reflect the natural variability of laboratory values.

Contextual Interpretation:

Test results must be interpreted in context, considering factors such as age, activity level, and time of day. A result outside the reference range does not necessarily indicate an abnormality.

Example: Heart Rate

* The average heart rate is around 70 beats per minute.
* An individual in excellent physical condition may have a pulse rate of 55, which is still considered normal.
* During strenuous activity, a heart rate of 120 beats per minute is expected.