[Correlation between osmolarity and specific gravity of urine. Changes caused by the presence of abnormal solutes]

There is a high correlation index (0.97) in the measurement of urine osmolality and specific gravity in healthy children and adults and in children with renal disease without heavy proteinuria or glucosuria. This is a useful tool, because osmometers are not used in many laboratories, but specific gravity is of general use, so that urine concentration in mOsm/kg. can be derived from the specific gravity. The same parameters in urines with heavy proteinuria or glucosuria were also measured and the correlation index and the modifications per gram of abnormal solute that should be applied in order to obtain the correct urine concentration figures, were established.