Estimation of daily sodium and potassium excretion from overnight urine of Japanese children and adolescents

Table 2 Urinalysis of the validation group (n = 34)

	First operation	Second operation
24 h urine (U₂₄)
Collection periods (t_clct), min	1367 ± 86	1379 ± 69
Volume (VoU), mL	981 ± 446	932 ± 406
NaU₂₄, mEq L⁻¹ (mmol L⁻¹)	155.7 ± 49.5	166.6 ± 48.6
KU₂₄, mEq L⁻¹ (mmol/L⁻¹)	44.14 ± 16.4	49.4 ± 20.5
CrU₂₄, mg dL (× 10/113 mmol L⁻¹)	108.0 ± 47.3	119.4 ± 47.8
[Na/Cr]U₂₄, mEq L⁻¹/mg dL⁻¹	1.63 ± 0.65	1.56 ± 0.55
[K/Cr]U₂₄, mEq L⁻¹/mg dL⁻¹	0.46 ± 0.26	0.43 ± 0.12
Na₂₄, mg d⁻¹	3346 ± 1082	3476 ± 1184
K₂₄, mg d⁻¹	1587 ± 483	1723 ± 664
Cr₂₄, mg d⁻¹	970 ± 313	1045 ± 311
Overnight urine (U_m)
NaU_m, mEq L⁻¹ (mmol L⁻¹)	118.4 ± 47.7	119.1 ± 53.3
KU_m, mEq L⁻¹ (mmol L⁻¹)	40.8 ± 16.3	35.0 ± 16.6
CrU_m, mg dL⁻¹ (× 10/113 mmol L⁻¹)	152.5 ± 59.0	133.9 ± 57.5
[Na/Cr]U_m, mEq L⁻¹/mg dL⁻¹	0.93 ± 0.60	1.00 ± 0.43
[K/Cr]U_m, mEq L⁻¹/mg dL⁻¹	0.29 ± 0.12	0.28 ± 0.10

NaU, KU, CrU: sodium, potassium, and creatinine concentrations in urine, respectively; [Na/Cr]U, [K/Cr]U, [Na/K]U: ratios of sodium-to-creatinine, potassium-to-creatinine, and sodium-to-potassium concentrations in urine, respectively; U₂₄, U_m: 24-h urine, and overnight urine, respectively; Na₂₄, K₂₄, Cr₂₄: measured daily urinary excretion of sodium, potassium, and creatinine, respectively

ISSN: 1347-4715