Radiology Coding Alert

Watch documentation for confirmation of stricture or obstruction.

When ICD-10 is finally implemented in 2014, you’ll be able to use codes to more accurately represent the cause of hydronephrosis. Here’s how your ICD-9 and ICD-10 options compare.

Diagnosis: Hydronephrosis refers to the swelling of a kidney because of urine backup.

ICD-9-CM Code:

591, Hydronephrosis

ICD-10-CM Codes:

N13.1, Hydronephrosis with ureteral stricture, not elsewhere classified

N13.2, Hydronephrosis with renal and ureteral calculous obstruction

N13.30, Unspecified hydronephrosis

N13.39, Other hydronephrosis

ICD-9 coding rules: Code 591 for hydronephrosis is one of the few valid 3-digit ICD-9 codes. Diagnoses reportable to 591 include hydrocalycosis and hydroureteronephrosis, as well as hydronephrosis. However, if documentation shows congenital hydronephrosis, you should instead use 753.29 (Other obstructive defect of renal pelvis and ureter). Hydroureter is also excluded from 591 and is instead coded to 593.5 (Hydroureter).

ICD-10 changes: Under ICD-10, your hydronephrosis coding will vary depending on whether the physician additionally documents a ureteral stricture or a renal and ureteral calculus obstruction. You’ll also have "other" and "unspecified" options. ICD-10, like ICD-9, points you elsewhere for congenital obstructive defects of renal pelvis and ureter (Q62.0 to Q62.3-). Other excluded diagnoses include calculus of kidney and ureter without hydronephrosis (N20.-), hydronephrosis with ureteropelvic junction obstruction (Q62.1-), chronic obstructive pyelonephritis (N11.1), and hydronephrosis diagnoses with infection (N13.6).

Documentation: The physician already should be documenting the type of hydronephrosis the patient has as well as whether there are infections, stones, or strictures associated with the hydronephrosis. This documentation will become crucial to proper code selection under ICD-10.

Coder tips: For hydronephrosis associated with tuberculosis, you’ll exchange ICD-9 codes from 016.0x (Tuberculosis of kidney ...) for ICD-10 code A18.11 (Tuberculosis of kidney and ureter).

Remember: CMS has finalized the ICD-10 compliance date of Oct. 1, 2014. When ICD-10 goes into effect, you should apply the code set and official guidelines in effect for the date of service reported. Learn more at www.cms.gov/ICD10/ and www.cdc.gov/nchs/icd/icd10cm.htm#10update.