ICD-9-CM 591
CMS Source: final ICD-9-CM release (version date October 1, 2014). Retired from U.S. claims after September 30, 2015.FacebookXLinkedInPrint

591 is a legacy ICD-9-CM diagnosis code for hydronephrosis. It was valid on U.S. claims through September 30, 2015 and cannot be reported for services on or after October 1, 2015, when ICD-10-CM replaced the ICD-9 code set. Under the CMS General Equivalence Mappings, its ICD-10-CM replacement is N13.30 (Unspecified hydronephrosis), flagged as an approximate match.

Code Identity

ICD-9-CM Code
591
Valid for Submission
No — Legacy Code
Code Describes
Hydronephrosis
Short Description
Hydronephrosis
Same as the full description in the CMS dataset.
Parent Block
591 Hydronephrosis
ICD-10-CM Replacement
N13.30 (approximate)

Convert 591 to ICD-10-CM

Based on the final CMS General Equivalence Mappings (GEMs), 591 crosswalks to the following ICD-10-CM code.

ICD-10-CM
N13.30 Unspecified hydronephrosis
Approximate The match is approximate rather than exact.

Index of Diseases References

Entries in the final ICD-9-CM Index to Diseases and Injuries that point to 591. Tap the icons for the official index conventions.

  • Atrophy atrophic
    • hydronephrosis 591
    • kidney senile SEE ALSO Sclerosis renal 587
      • hydronephrotic 591
  • Contraction contracture contracted
    • kidney granular secondary SEE ALSO Sclerosis renal 587
      • hydronephritic 591
  • Cyst mucus retention serous simple
    • kidney congenital 753.10
      • calyceal SEE ALSO Hydronephrosis 591
      • pyelogenic SEE ALSO Hydronephrosis 591
  • Hydrocalycosis SEE ALSO Hydronephrosis 591
  • Hydrocalyx SEE ALSO Hydronephrosis 591
  • Hydronephrosis 591
    • atrophic 591
    • due to S. hematobium 120.0
    • early 591
    • functionless infected 591
    • infected 591
    • intermittent 591
    • primary 591
    • secondary 591
    • tuberculous SEE ALSO Tuberculosis 016.0
  • Hydroureteronephrosis SEE ALSO Hydronephrosis 591
  • Infection infected infective opportunistic 136.9
    • hydronephrosis 591
  • Lymphoma malignant M9590 3 202.8
    • non Hodgkin s type NEC M9591 3 202.8
  • Pelvioectasis 591
  • Pyelohydronephrosis 591

Information for Patients

Kidney Diseases

You have two kidneys, each about the size of your fist. They are near the middle of your back, just below the rib cage. Inside each kidney there are about a million tiny structures called nephrons. They filter your blood. They remove wastes and extra water, which become urine. The urine flows through tubes called ureters.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Questions About 591

Is 591 (hydronephrosis) still a valid code?

No. This code belonged to ICD-9-CM, which the United States retired after September 30, 2015. Claims with dates of service on or after October 1, 2015 must use ICD-10-CM codes, such as its replacement N13.30.

What is the ICD-10 replacement for 591?

The General Equivalence Mappings crosswalk this code to ICD-10-CM N13.30 (Unspecified hydronephrosis). The match is flagged as approximate, so confirm it against the clinical documentation before use.

What did 591 mean?

In the final ICD-9-CM release, this code described hydronephrosis. It sat in block 591 Hydronephrosis under Diseases of the genitourinary system (580–629).