Selected urine values. Common-stone formers are represented by open circles, bypass patients by filled circles, and normal subjects by triangles. The values for a comparison of stone formers with bypass patients are as follows: urine calcium, 312 ± 89 versus 81 ± 29; oxalate, 40 ± 13 versus 106 ± 11; citrate, 485 ± 278 versus 144 ± 107; supersaturation with respect to CaOx monohydrate, 11 ± 4 versus 5 ± 2; and supersaturation with respect to calcium phosphate, 1.4 ± 8 versus 0.09 ± .05. P < 0.01 for all values by t test and Kolmogorov-Smirnov nonparametric testing. For normal subjects, values for calcium, oxalate, citrate, supersaturation with respect to CaOx, and supersaturation with respect to calcium phosphate were 113 ± 67, 32 ± 9, 482 ± 193, 3.5 ± 1.3, and 0.42 ± .16, respectively; P = < 0.01 versus stone formers by t test and Kolmogorov-Smirnov for calcium, supersaturation with respect to CaOx, and supersaturation with respect to calcium phosphate; P < 0.0001 versus bypass by t test and Kolmogorov-Smirnov for oxalate; P = 0.022 by t test and 0.0001 by Kolmogorov-Smirnov for supersaturation with respect to calcium phosphate; and P = 0.03 by t test and was not significant by Kolmogorov-Smirnov for citrate. The other comparisons of normal subjects to patient groups were not significant by both t test and Kolmogorov-Smirnov. SS, supersaturation.