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Table 3 Urinary volume, pH, solute concentrations, Ca/Cit ratio, and AP indexes in 12-h daytime and 12-h overnight urine samples of healthy and stone-forming adults

From: Effect of sample time on urinary lithogenic risk indexes in healthy and stone-forming adults and children

  Healthy adults (n = 82) Stone forming adults (n = 67)
12-h day 12-h night p-value 12-h day 12-h night p-value
Volume (mL/12 h) 870 (600–1165) 650 (481–1010) 0.001 920 (700–1200) 780 (600–1135) 0.071
Creatinine (mg/dL) 940 (560–1310) 1025 (670–1563) 0.002 736 (562–1233) 946 (553–1224) 0.192
Calcium (mg/L) 90 (72–161) 133 (63–201) 0.060 123 (84–167) 142 (90–184) 0.031
Magnesium (mg/L) 52 (37–81) 79 (50–109) < 0.001 49 (38–68) 68 (50–90) < 0.001
Oxalate (mg/L) 15 (11–19) 16 (11–23) 0.04 18 (14–24) 21 (15–27) 0.003
Phosphorous (mg/L) 469 (353–683) 651 (442–1085) < 0.001 473 (314–622) 581 (382–773) < 0.001
Uric acid (mg/L) 426 (278–556) 372 (226–526) 0.259 395 (263–499) 338 (241–473) 0.031
Citrate (mg/L) 495 (315–754) 408 (232–710) 0.016 347 (223–531) 324 (205–434) 0.047
pH 6.27 (5.95–6.71) 5.64 (5.43–5.98) < 0.001 6.12 (5.71–6.60) 5.79 (5.49–6.16) < 0.001
Ca/Cit (mg/mg) 0.21 (0.15–0.30) 0.25 (0.18–0.42) < 0.001 0.34 (0.21–0.44) 0.43 (0.26–0.64) < 0.001
AP (CaOx) index 0.64 (0.49–0.90) 0.66 (0.46–1.13) 0.057 1.10 (0.66–1.54) 1.35 (0.90–1.84) 0.001
AP (CaP) index 4.85 (1.09–18.24) 0.33 (0.06–2.49) < 0.001 3.41 (0.36–15.30) 0.93 (0.07–7.87) 0.001
  1. Results are expressed as median (P25-P75)