How to Calculate Reference Range?

The common formula to calculate the reference range is: mean±1.96x SD.

What is a normal reference range?

Lab results are often shown as a set of numbers known as a reference range. A reference range may also be called "normal values." You may see something like this on your results: "normal: 77-99mg/dL" (milligrams per deciliter). Reference ranges are based on the normal test results of a large group of healthy people.

What is the 95 reference range?

The 95% limits are often referred to as a “reference range”. For many biological variables, they define what is regarded as the normal (meaning standard or typical) range. Anything outside the range is regarded as abnormal.