The International System of Units (S.I.) and its Application to Clinical Chemistry

As part of the national programme of metrication, clinical chemistry laboratories in the U.K. are in process of changing their methods of reporting results so as to express them in SI units.

This article gives examples of the effects of adopting SI units on the numerical expression of chemical results, and discusses practical aspects which may facilitate their introduction and acceptance in medical practice. For many chemical measurements, the change to SI units will cause substantial alterations in the numerical data with which clinicians will have to deal, and awareness of this fact will be necessary if serious mistakes in the management of patients' illnesses are to be avoided. The tasks of laboratory staff in planning and carrying out the necessary educational programmes are considered.