2026 ICD-10-CM Diagnosis Code N13.39Other hydronephrosis
ICD-10-CM Codes›N00–N99›N10-N16›N13
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
N13.39 is a billable ICD-10-CM diagnosis code for other hydronephrosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 693 through 694, 791, 793. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 226 closely related codes. Coders also document this condition as acquired hydronephrosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified diseases of kidney and ureters.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acquired hydronephrosis
- Acquired hydronephrosis due to urinary bladder obstruction
- Acquired obstruction of urinary tract
- Dilatation of renal pelvis
- Hydroureter
- Hydroureteronephrosis
- Obstructive hydronephrosis
- Obstructive hydroureter
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Hydronephrosis
abnormal enlargement or swelling of a kidney due to dilation of the kidney calices and the kidney pelvis. it is often associated with obstruction of the ureter or chronic kidney diseases that prevents normal drainage of urine into the urinary bladder.Pyonephrosis
distention of kidney with the presence of pus and suppurative destruction of the renal parenchyma. it is often associated with renal obstruction and can lead to total or nearly total loss of renal function.
Patient EducationClinical
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.
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Convert N13.39 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About N13.39Overview
What is the ICD-10 code for other hydronephrosis?
The ICD-10-CM code for other hydronephrosis is N13.39 (sometimes written as N1339). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is N13.39 (Other and unspecified hydronephrosis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other hydronephrosis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does N13.39 group to?
When other hydronephrosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 693, 694, 791, 793, with relative weights from 0.7817 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.
Is N13.39 a CC or MCC?
CMS lists N13.39 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 226 closely related codes in its exclusion list.
What is the ICD-9 equivalent of N13.39?
Under the General Equivalence Mappings, other hydronephrosis converts to ICD-9-CM 591 (hydronephrosis). The mapping is approximate, so confirm the match fits the documentation.
