Electrical conductivity of 24-hour urine is decreased in patients with calcium oxalate urolithiasis

Kamonchat  Boonkam; Natcha  Madared; Pakpum  Somboon; Alongkorn  Pimpin; Chanchai  Boonla

Authors

Kamonchat Boonkam Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
Natcha Madared Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
Pakpum Somboon Biomedical Engineering program, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
Alongkorn Pimpin Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
Chanchai Boonla Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand

Keywords:

Calcium oxalate, electrical conductivity, kidney stone, urine specific gravity, 24-hour urine

Abstract

Background: Electrical conductivity (EC) of urine depends on the ionic substance-to-water ratio. Calcium oxalate (CaOx) is the most common type of urinary stone, and its formation is driven by decreased urine volume, increased lithogenic substances, and decreased stone inhibitory compounds (specifically citrate). Low urinary citrate excretion (hypocitraturia) is a prominent risk factor in Thai urolithiasis patients.

Objective: To measure the urinary EC, urinary calcium, and urine specific gravity in CaOx stone patients compared with non-stone forming (NSF) subjects.

Methods: The urinary EC was measured in 24-hour urine samples obtained from 42 CaOx stone patients and 121 NSF subjects. Urinary calcium and urine specific gravity were measured to evaluate whether they were associated with the urinary EC.

Results: The urinary EC of CaOx stone patients was significantly lower than the NSF subjects. The urinary EC level was positively correlated with urine specific gravity, but not urinary calcium. At the selected cutoff of 14.3 mS/cm, the sensitivity, specificity, and accuracy of the urinary EC for diagnosing CaOx urolithiasis were 74.0%, 50.0%, and 56.0%, respectively. In CaOx stone group, patients who had low urinary citrate had lower urinary EC than patients who had high urinary citrate. Experimentally, we demonstrated in artificial urine that citrate concentrations actively influenced the EC values. Decreased citrate level directly caused decreased EC value.

Conclusion: The EC of 24-hour urine in CaOx stone patients was decreased relative to the NSF individuals. The urinary EC was linearly correlated with urine specific gravity. Low urinary EC observed in CaOx stone patients possibly resulted from a low urinary citrate excretion that was highly prevalent in the stone patients. In addition, gradual decrease in citrate level caused a gradual decrease in EC level.

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References

Boonla C. Oxidative Stress in Urolithiasis. Rijeka: Reactive Oxygen species (ROS) in Living Cells; 2018. p.129-159.

https://doi.org/10.5772/intechopen.75366

Khan SR, Pearle MS, Robertson WG, Gambaro G, Canales BK, Doizi S, et al. Kidney stones. Nat Rev Dis Primers 2016;2:16008.

https://doi.org/10.1038/nrdp.2016.8

Tosukhowong P, Boonla C, Ratchanon S, Tanthanuch M, Poonpirome K, Supataravanich P, et al. Crystalline composition and etiologic factors of kidney stone in Thailand: Asian Biomed 2007;1:87-95.

Goldberg H, Grass L, Vogl R, Rapoport A, Oreopoulos DG. Urine citrate and renal stone disease. CMAJ 1989;141:217-21.

Pak CY. Citrate and renal calculi: an update. Miner Electrolyte Metab 1994;20:371-7.

Tosukhowong P, Boonla C, Tungsanga K. Hypocitraturia: Mechanism and therapeutic and strategies. Thai J Urol 2012;33:98-105.

Youngjermchan P, Pumpaisanchai S, Ratchanon S, Pansin P, Tosukhowong P, Tungsanga K, et al. Hypocitraturia and hypokaliuria: major metabolic risk factors for kidney stone disease. Chula Med J 2006; 50:605-21.

Gorbunov A, Gromov Y, Egorov V. The calculation of the impedance of biological tissue on the model of Yamamoto in the process of galvanic effects. J Phys: Conf Ser 2019;1278:012037.

https://doi.org/10.1088/1742-6596/1278/1/012037

Gruner O. The electro-conductivity of body fluids. Lancet 1906;168:323.

https://doi.org/10.1016/S0140-6736(01)30596-2

Khan SR, Kok DJ. Modulators of urinary stone formation. Front Biosci 2004;9:1450-82.

https://doi.org/10.2741/1347

Fazil Marickar YM. Electrical conductivity and total dissolved solids in urine. Urol Res 2010;38:233-5.

https://doi.org/10.1007/s00240-009-0228-y

Chhabra HL, Manocha KK. A new test for idiopathic kidney stones. Indian J Med Res 1985;81:68-70.

Manocha KK, Kuhar SS, Chhabra HL. Physical properties including pH & specific electrical conductivity of urine in idiopathic kidney stone formers. Indian J Med Res 1987;86:124-7.

Chhabra HL, Manocha KK. Idiopathic kidney stone formation-where and why? Br J Urol 1991;68:568-70.

https://doi.org/10.1111/j.1464-410X.1991.tb15416.x

Chutipongtanate S, Thongboonkerd V. Systematic comparisons of artificial urine formulas for in vitro cellular study. Anal Biochem 2010;402:110-2.

https://doi.org/10.1016/j.ab.2010.03.031

Zuckerman JM, Assimos DG. Hypocitraturia: pathophysiology and medical management. Rev Urol 2009;11:134-44.

Sun XY, Gan QZ, Ouyang JM. Calcium oxalate toxicity in renal epithelial cells: the mediation of crystal size on cell death mode. Cell Death Discov 2015;1:15055.

https://doi.org/10.1038/cddiscovery.2015.55

Ster A, Safranko S, Bilic K, Markovic B, Kralj D. The effect of hydrodynamic and thermodynamic factors and the addition of citric acid on the precipitation of calcium oxalate dihydrate. Urolithiasis 2018;46:243-56.

https://doi.org/10.1007/s00240-017-0991-0

Zhang J, Zhang W, Putnis CV, Wang L. Modulation of the calcium oxalate dihydrate to calcium oxalate monohydrate phase transitionwith citrate and zinc ions. Cryst Eng Comm 2021;23:8588-600.

https://doi.org/10.1039/D1CE01336J

Prot-Bertoye C, Vallet M, Houillier P. Urinary citrate: helpful to predict acid retention in CKD patients? Kidney Int 2019;95:1020-2.

https://doi.org/10.1016/j.kint.2019.01.019

Saepoo S, Adstamongkonkul D, Tosukhowong P, Predanon C, Shotelersuk V, Boonla C. Comparison of urinary citrate between patientswith nephrolithiasis and healthy controls. Chula Med J 2009; 53:51-65.

Silverio AA, Chung WY, Cheng C, Wang HL, Kung CM, Chen J, et al. The potential of at-home prediction of the formation of urolithiasis by simple multi-frequency electrical conductivity of the urine and the comparison of its performance with urine ion-related indices, color and specific gravity. Urolithiasis 2016;44:127-34.

https://doi.org/10.1007/s00240-015-0812-2

Alexander RT. Kidney stones, hypercalciuria, and recent insights into proximal tubule calcium reabsorption. Curr Opin Nephrol Hypertens 2023;32:359-65.

https://doi.org/10.1097/MNH.0000000000000892

Letavernier E, Daudon M. Vitamin D, Hypercalciuria and kidney stones. Nutrients 2018;10:366.

https://doi.org/10.3390/nu10030366

Mandrekar JN. Receiver operating characteristic curve in diagnostic test assessment. J Thorac Oncol 2010;5:1315-6.

https://doi.org/10.1097/JTO.0b013e3181ec173d