Easy-to-use equations for the estimation of urine relative saturation in the assessment of risk of recurrence in urinary stones formers.

It is a fact that recurrence of urinary stones is a common medical problem. One of the key factors used in determining the risk of urinary stone-formation is the urine relative saturation in the major constituents of lithiasis. Nomograms were developed in the 1970's to estimate the relative saturation of urine. We present here easy-to-use mathematical equations derived from these nomograms. These equations can be integrated directly in the LIS of any laboratories, and can be used as a tool in the treatment and prevention of recurrent stone-formation.