Analysis of urinary calculi by chemical methods

ABSTRACT

Two hundred twelve samples from 90 stones obtained from one hundred consecutive children with bladder stone disease [BSD] were analysed by qualitative and quantitative chemical methods. Majority [72%] of the stones were spherical in shape while 51% had mammilated surface. Children in older age group had heavier stones [P < 0.05]. The calculi were predominantly of mixed type [88.9%]. Calcium oxalate was the commonest [97.7%] compound detected by qualitative chemical method. The central portion of calculi showed a significantly higher [P < 0.02] occurrence of ammonium urate compared to the surface. Uric acid was present in surface layer in significantly higher [P < 0.05] number in patients with uninfected urine. On quantitative analysis calcium and oxalate occurred in significantly higher [P < 0.01] percentage in surface layers, while urate occurred more frequently [P < 0.05] in the central portion of calculi. On comparing the two chemical methods of stone analysis, a good agreement was seen in the detection of calcium, oxalate and urate but phosphate was missed in 39% samples by the qualitative method and in 10% samples by quantitative method: