Standardized Reporting of Laboratory Data

The international trend to standardization of measurements may have considerable impact on the practice of medicine in this country. The International System (SI) of measurement is based on seven fundamental quantities — mass, time, length, luminous intensity, electric current, thermodynamic temperature and amount of substance. In medicine, implementation of the SI for reporting of laboratory data will mean a change from mass units (e.g., milligrams per hundred millilitres) to molar units (e.g., moles per litre), which are the appropriate units for amounts of substances. This will create a situation in which physicians will not comprehend results initially, and yet the system permits quantitative relations between substances in body fluids to be revealed that are masked when traditional units are used. Implementation of the SI for reporting of laboratory data will be difficult, but use of the system should ultimately lead to better understanding of pathologic processes and the improved care of patients. (N Engl J Med 290:368–373, 1974)