Analysis of Renal Stone Composition Using Fourier Transform Infrared Spectroscopy: A Cross-sectional Study of 3,789 Cases

Background: Renal stones, commonly known as kidney stones, are a significant urological condition caused by the crystallization of dietary minerals in the kidneys. Their composition varies and can include calcium oxalate, calcium phosphate, uric acid, cystine, and other minerals. Fourier transform infrared (FTIR) spectroscopy, a semi-quantitative and automated method, is an advanced technique for determining stone composition, aiding in personalized treatment and prevention of recurrence. Objectives: The study aims to: • Analyze the mineral composition of renal stones using FTIR spectroscopy. • Classify the mineral components of renal stones. • Study the trends and morphological characteristics of stones. Methods: This cross-sectional study analyzed 3,789 renal stones received from August 2019 to May 2024. The stones were prepared and analyzed using the Agilent Cary 630 FTIR Analyzer. Data on mineral composition and morphology were collected and processed to identify various mineral trends and stone compositions. Results: Demographics: 76.3% of stones were from male patients, with the highest incidence in the 31–40 age-group. Composition: 93.5% of stones were of mixed composition, with calcium oxalate monohydrate being the most prevalent (38.3%). Rare compositions: Stones with rare compositions, such as xanthine and 2, 8-dihydroxyadenine, were identified, providing insight into specific metabolic disorders. Conclusion: Fourier transform infrared spectroscopy provides reliable results for stone composition, enabling effective and individualized treatment plans. The predominance of mixed stones underscores the need for multifactorial treatment approaches addressing dietary, metabolic, and infectious factors. Further research, particularly using advanced techniques like genetic testing, may enhance understanding of stone formation.