What is known:
• The role of urine calcium as a promoter in calcium oxalate urolithiasis is well established.
• Seldom used calcium/citrate ratio is acknowledged as a risk factor for calcium/oxalate urolithiasis.
What is new:
• The values of calcium and citrate in clinically and genetically proven idiopathic calcium oxalate urolithiasis make calcium/citrate ratio useful for diagnostic purposes in such stone formers.
• Rarely used calcium independent oxalate/(citrate x glycosaminoglycans) ratio serves as the second best high specificity marker for idiopathic calcium oxalate urolithiasis.