Hydronephrosis ICD-10-CM codes

N13.30 is unspecified hydronephrosis and N13.39 is other hydronephrosis. When the cause is documented, use the combination code: N13.0 with ureteropelvic junction (UPJ) obstruction, N13.1 with ureteral stricture, and N13.2 with renal and ureteral calculous obstruction. Hydroureter is N13.4 and pyonephrosis is N13.6.

N13.2 is a combination code, so a stone causing hydronephrosis is reported as N13.2 alone, not N13.2 plus N20.0, N20.1, or N20.2. Stones without obstruction are coded to N20.-. Vesicoureteral reflux is coded from N13.7-, split by whether there is reflux nephropathy and hydroureter.

Congenital hydronephrosis, including prenatally detected cases, is Q62.0. Hydronephrosis in pregnancy is coded from O26.83- (pregnancy-related renal disease) by trimester, such as O26.831. Acute kidney injury from obstruction is coded additionally with N17.9. See the kidney stones guide for N20 detail.