Health and Disease from the Point of View of the Clinical Laboratory

Abstract

I became involved in the philosophical problems of medicine by introducing together with Saris in 1969, rather boldly and unsuspectingly, the concept of reference values [20]. As arrangers of a congress we brought up the topic because we thought it might be interesting. The mental process leading up to this concept can be traced back to about 10 years earlier when several facts attracted my attention: I had been taught that Nature, including the results of laboratory tests, was distributed in a Gaussian manner, but in a study on serum vitamin B₁₂ we found that this was not so, which puzzled me [19]. Second, when returning to clinical work from experimental research I noticed that the controls were unsatisfactory. In experimental work you meticulously arrange that the controls are very similar to the objects of the actual experiment. Diseases and patients may be regarded as experiments made by Nature, but the controls, and the data derived from them, i.e., the normal values, were used without paying attention to whether they were comparable to the patients and their data. The normal values were usually derived from young, ambulant persons, frequently hospital personnel, whereas the patients tended to be old and bedridden. Third, I realised that the word normal was ambiguous, meaning, e.g., frequent, non-pathological and Gaussian [18] and others agreed ([24], [29]). The term ‘reference values’ represents a wider concept than normal values covering data from both healthy, unselected and diseased individuals or groups of individuals, “negative and positive clinical controls”.