Biochemical urinalysis of healthy kidney and stone-generating kidney in unilateral urolithiasis

Introduction: Oxalate, calcium, uric acid, and citrate are among the most widely known biochemical factors for urinary stone formation. In most cases, urolithiasis occurs as unilateral despite the role of systemic metabolic factors in kidney stone formation. Objectives: The present research aimed to compare these urinary biochemical factors in healthy and stone-generating kidneys in patients with unilateral urolithiasis. Patients and Methods: Forty patients with unilateral urolithiasis participated in this cross-sectional, descriptive-analytical study. The patients were hospitalized in kidney surgery and kidney urology ward of Kashani hospital of Shahrekord, southwest Iran. After the implementation of crushing stone using transurethral lithotripsy (TUL), 5-10 cc of urinary sample was collected from each kidney. An AutoAnalyzer (Mindray Company, Bs–360 model) and laboratory kits (Bionic Company) were used to measure calcium, uric acid, and creatinine. Moreover, a manual method and Darman Faraz Kave company kits were applied to measure the levels of oxalate and citrate. Results on the healthy and stone-generating kidneys of each patient were separately analyzed using the Stata 13 software. Results: The difference in the mean ratio of uric acid, oxalate, and citrate to creatinine in the healthy kidneys and stone-generating kidneys was not significant. However, the mean UCa/UCr ratio in the healthy kidneys was 0.27±0.07 and relatively greater than that in the stone-generating kidneys (0.11±0.04) (P = 0.06). Conclusion: The studied topical factors and secretory disorders had not any significant relationship with unilateral urolithiasis. The cause of unilateral urolithiasis should be searched in other factors such as metabolic factors, main positions of individual during 24 hours and sleeping, and anatomic disorders of kidney stone, or multifactorial.