Why and when to modify or adopt new diagnostic cut-off values in laboratory tests?

Abstract

Diagnostic cut-off values for laboratory tests have generally been established based on a reference range obtained from a "healthy" population. However, there may be circumstances in which it is required to modify these cut-off values for specific pathologies. This is the case of diabetes mellitus (DM), where the risk of its development is a continuum that can start from blood glucose levels considered “normal”. While the interpretation of a test with binary results is straightforward, the interpretation of a test with continuous results is not so simple. It is difficult to establish a gold standard for the diagnosis of conditions such as, for example, arterial hypertension and hypercholesterolemia, which have constantly changed based on the concrete evidence of the benefit of reducing their values to a greater or lesser extent depending on the patient's condition. It has been even more difficult to establish a gold standard for the diagnosis of DM.