Clinical and laboratory tests in clinical medicine include a range of measurements that may be categorized as “normal range” tests, positive or negative tests, or contextual tests. Normal range test results are quantitative and are compared to a reference interval or range provided by the laboratory. Positive or negative tests are also quantitative tests and characteristically have a cutoff value that specifies the result. Contextual tests require a context, a physiological condition, to correctly interpret the result. A closer examination of reference intervals suggests that these also are contextual. The fact that there is a range of apparently normal values indicates the presence of cultural, biological, physiological and behavioral diversity in the population sampled to determine normality. As such, the reference interval describes the population from which it was determined and may have utility in this regard.
Author contributions: Alan N. Charney, MD, conceived, researched and wrote the submitted manuscript. Jordan T. Dourmashkin, PA-C researched and wrote the submitted manuscript. All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
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