Britannica
Sources used in this answer
Why can healthy people sometimes receive an abnormal laboratory test result?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
diagnosis
Magnetic resonance imaging (MRI) is a powerful diagnostic technique that is used to visualize organs and structures inside the body without the need for X-rays or other radiation.
Healthy individuals may receive an abnormal laboratory test result primarily due to the inherent nature of how "normal" values are defined and the limitations of testing procedures.
- Statistical Variability: Normal reference values are typically based on 95 percent of the healthy population. By definition, this means that approximately 1 out of every 20 healthy individuals will have a test result that falls outside the "normal" range, appearing abnormal despite the absence of disease.12
- Lack of Specificity: No diagnostic test is perfect. If a test lacks high specificity, it can yield a false positive—a result that incorrectly indicates the presence of a condition that does not actually exist.13
- Biological Variability: There is no sharp line dividing normal and abnormal values. Many physiological measurements vary significantly based on factors such as age, gender, and environmental conditions. Because reference values are often means derived from large groups, an individual’s unique baseline may naturally fall outside these generalized ranges without indicating illness.12
Ultimately, because health is a complex and somewhat nebulous condition, test results must be interpreted by a physician in the context of the individual's overall health rather than viewed in isolation.2