Chemical constituent of urinary stone is important for the management and the prevention of recurrence. We performed chemical analysis of the urinary stone and investigatedits chemical constituent.

From January 2003 to December 2005, stone fragments were collected after extracorporeal shock wave lithotripsy (ESWL, n=43), or removal by endoscopic procedure such as ureteroscopy (URS, n=93) and open surgical procedure such as cystolithotomy (n=8). So we had stone fragments from 144 patients totally.

80 stone fragments were collected from male (55.6%), 64 stones from female (44.4%), and male to female ratio was 1.25 : 1. The mean age between males (mean age ; 47.2 years old)and females (mean age ,47.9 years old) was not different. The most frequently found location of urinary stones was ureter(91.0%) Of 144 patients in urine analysis,54 had pyuria (37.5%). The most frequently found constituent in stone fragments was that of calcium(n=119 , 82.6%). The 2nd constituent was phosphate (n=82 ; 56.9%). The 3^rd was uric acid(n=33 ; 22.9%). The other constituents were ammonium(n=24 ; 16.6%) , carbonate (n=18 , 12.5%), magnesium (n=11 ; 7.6%). oxalate (n=3 ; 2.1%). Struvite stone (MAP stone ; magnesium+ammonium+phosphate)were found in 5 patients (3.5%) All of 5 patients having strivite stone had pyuria(100%).

Calcium is the most common chemical constituent in urinary stone. Urinary infection was complication in 100% of patients with MAP stones.