A simple method for "reference range" estimation from routine laboratory data

A simplified method is presented to estimate reference ranges from hospital laboratory data. It is based on a combination of graphical estimation of relative sizes of normal and abnormal populations and the "mode-center" concept in which the mode of the total population centers on the 50% cumulative frequency of the normal population. This method can be applied to determine reference ranges even though the data source contains abnormally high and/or low values. The reference ranges obtained for BUN and calcium from in-patient and out-patient sources by this method were found to be similar to those reported for "healthy" subjects.