N20  Calculus of kidney and ureter  
Excludes:  with hydronephrosis


N20.0  Calculus of kidney  
Nephrolithiasis NOS
Renal calculus or stone Staghorn calculus Stone in kidney 

N20.1  Calculus of ureter  
Ureteric stone


N20.2  Calculus of kidney with calculus of ureter  
N20.9  Urinary calculus, unspecified  
Calculous pyelonephritis

N21  Calculus of lower urinary tract  
Includes:  with cystitis and urethritis


N21.0  Calculus in bladder  
Calculus in diverticulum of bladder
Urinary bladder stone 

Excludes:  staghorn calculus


N21.1  Calculus in urethra  
N21.8  Other lower urinary tract calculus  
N21.9  Calculus of lower urinary tract, unspecified 
N22*  Calculus of urinary tract in diseases classified elsewhere  
N22.0* 
Urinary calculus in schistosomiasis [bilharziasis]


N22.8*  Calculus of urinary tract in other diseases classified elsewhere 
N23  Unspecified renal colic 