Table 1.

Comparison of the various methods for assessing the risk of crystalluria and recurrent stone formation.

Procedure	No. of measurements	Information generated	Advantages	Disadvantages
RSS, SUPERSAT, EQUIL 2, EQUIL 93, SEQUIL, JESS	12–14	Supersaturation of urine before any crystalluria for CaOx, CaP, Bru, UA, MAP, NH4U, NAU, CaU2, cystine (only for methods where cystine is measured)	‘Gold standard’ for measuring the RSS of urine for most stone constituents	Many analytes, expensive, no information on growth and aggregation potential of crystals in urine
Tiselius Indices	7	CPs of CaOx and CaP in urine before any crystalluria	Combine supersaturation and some measures of the growth and aggregation potential of crystals in urine. Provide some information on the individual urinary risk factors responsible for abnormalities in CP. Fewer measures than for RSS	Provide no information about the CPs of UA, MAP or cystine
RRFA	7	CPs of CaOx, CaP and UA in urine before any crystalluria	Combine supersaturation and some measures of growth and aggregation potential of crystals in urine. Provide some information on the individual urinary risk factors responsible for abnormalities in CP. Fewer measures than for RSS	Provide no information about the CPs of UA, MAP or cystine
BONN-Risk Index	2	CP of CaOx and UA in filtered urine	Very few measurements vs. all other methods	Provides no information about CPs of CaP, UA, MAP or cystine. Provides no information on the individual urinary risk factors responsible for any abnormalities in the CP of CaOx