STONE Nephrolithometry Score for Renal CalculiLoading...Stone size in mm^20-399+1400-799+2800-1599+3> 1600+4Tract length (mm)≤ 100+1> 100+2Obstruction (hydronephrosis)No/mild hydronephrosis+1Moderate/severe hydronephrosis+2Number of calyces with calculi1-2+12+3Full staghorn stone+3Essence (stone density in Hounsfield units)≤ 950+1> 850+2