Question

An analyte has been discovered ( so it's new) in the Tobago population. Define the term reference range and explain possible approaches to determine a reference range. Indicating factors that affect reference range.

Answer 1

Listen to pronunciation. (REH-frents raynj) In medicine, a set of values that a doctor uses to interpret a patient's test results. The reference range for a given test is based on the results that are seen in 95% of the healthy population.

A reference range can vary between different laboratories when a collection of people who are considered 'normal' are used to establish a reference range for a given blood test. Complex mathematics are applied to allow for a natural variation within this chosen collection of people and therefore the reference range.

Values within the reference range (WRR) are those within the normal distribution and are thus often described as within normal limits (WNL). The limits of the normal distribution are called the upper reference limit (URL) or upper limit of normal (ULN) and the lower reference limit (LRL) or lower limit of normal (LLN). In health care–related publishing, style sheets sometimes prefer the word reference over the word normal to prevent the nontechnical senses of normal from being conflated with the statistical sense.

Factors that affect reference range:

By far, the most common factors that cause variations in reference values are age and/or sex. For example, the range used to evaluate a creatinine test result depends on a person's age and sex as shown in the table below.