Published: 26 Mar 2024

Reference Ranges for Lab Tests

Reference ranges (also known as standard ranges) are used by healthcare professionals to interpret test results in the context of a patient's health status.

Standard Reference Ranges

These ranges represent the typical (normal) values found in a healthy population. They typically include the prediction interval that covers 95% of the population.

Optimal Health Ranges

In contrast to standard ranges, optimal health ranges are based on concentrations or levels associated with optimal health or minimal risk of related complications or diseases.

Differences between Standard and Optimal Ranges

Optimal health ranges may differ significantly from standard ranges, especially for vitamins and blood lipids. Therefore, some test results tables include both standard and optimal ranges.

Optimal Levels

Optimal levels are typically close to the central tendency of values found in the population. For most substances, optimal levels are also those normally found in a healthy population.

Understanding Test Results

It's important to refer to the specific reference range provided by the lab that performed your test to determine if your results fall within normal limits. Most lab reports include information on:

* Reference range
* Units of measurement
* Accuracy limitations due to equipment and other factors

Why Reference Ranges Vary

Reference ranges may vary between labs due to differences in testing equipment, reagents, and analysis methods. This underscores the importance of using the range provided by the lab that performed your test.