Published: 12 Oct 2024

Reference Ranges for Medical Tests

Definition and Determination:

* The first step in establishing a reference range is defining the target population.
* A large sample of individuals considered "normal" is tested.
* The reference range is calculated by averaging the values and accounting for natural variations (within 2 standard deviations).
* This range represents the values found in 95% of the population, hence the term "reference range" instead of "normal range" (as 5% of results may lie outside it).

Population Considerations:

* "Normal" values can vary across different populations. For example, cholesterol target values are often tailored to specific groups.

Interpretation of Results:

* Test results should be interpreted in the context of individual circumstances, including:
* Medical history
* Current medications
* Other diagnostic findings

Blood Sample Analysis:

* Blood samples are commonly used to measure various health parameters, such as:
* Complete blood count
* Hormone and electrolyte levels
* Leukocyte counts
* Blood plasma protein levels

Comparison to Reference Ranges:

* By comparing blood properties to reference ranges, medical professionals can determine the presence or absence of abnormalities, diagnose disorders, monitor conditions, and assess treatment effectiveness.