2026 ICD-10-CM Diagnosis Code N13.6Pyonephrosis
ICD-10-CM Codes›N00–N99›N10-N16›N13
- Billable — Valid for Submission
- Not Chronic
N13.6 is a billable ICD-10-CM diagnosis code for pyonephrosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 689 through 690. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Urinary tract infections.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute pyonephrosis
- Acute pyonephrosis with renal medullary necrosis
- Acute pyonephrosis without renal medullary necrosis
- Chronic pyelonephritis
- Chronic pyonephrosis
- Chronic urinary tract infection
- Obstructive pyelonephritis
- Pyelonephritis associated with another disorder
- Pyonephrosis
- Recurrent obstructive pyelonephritis
- Recurrent urinary tract infection
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
Use Additional Code
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) - L02.91
- with calculus - N20.0
- with hydronephrosis - N13.6
- with infection - N13.6
- Calculus, calculi, calculous
- kidney (impacted) (multiple) (pelvis) (recurrent) (staghorn) - N20.0
- with calculus, ureter - N20.2
- with infection - N13.6
- congenital - Q63.8
- with infection - N13.6
- pyelitis (impacted) (recurrent) - N20.0
- with hydronephrosis - N13.6
- pyelonephritis (impacted) (recurrent)
- with hydronephrosis - N13.6
- ureter (impacted) (recurrent) - N20.1
- with calculus, kidney - N20.2
- with infection - N13.6
- with infection - N13.6
- urinary (duct) (impacted) (passage) (tract) - N20.9
- with infection - N13.6
- Constriction - See Also: Stricture;
- with infection - N13.6
- Contraction (s), contracture, contracted
- ureterovesical orifice (postinfectional) - N13.5
- with infection - N13.6
- perirenal (with ureteral obstruction) - N13.5
- with infection - N13.6
- retroperitoneal - K68.2
- with infection - N13.6
- Hydronephrosis (atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC - N13.30
- with
- infection - N13.6
- renal calculus - N13.2
- with infection - N13.6
- ureteral NEC - N13.1
- with infection - N13.6
- with infection - N13.6
- ureteropelvic junction (congenital) - Q62.11
- with infection - N13.6
- ureteral stricture NEC - N13.1
- with infection - N13.6
- Hydropyonephrosis - N13.6
- Hydroureter - See Also: Hydronephrosis; - N13.4
- with infection - N13.6
- Infection, infected, infective (opportunistic) - B99.9
- kidney (cortex) (hematogenous) - N15.9
- with calculus - N20.0
- with hydronephrosis - N13.6
- ureter (pelvic junction) - N13.5
- with
- hydronephrosis - N13.1
- with infection - N13.6
- Narrowing - See Also: Stenosis;
- with infection - N13.6
- with infection - N13.6
- Obstruction, obstructed, obstructive
- ureter (functional) (pelvic junction) NEC - N13.5
- with
- hydronephrosis - N13.1
- with infection - N13.6
- Ormond's disease (with ureteral obstruction) - N13.5
- with infection - N13.6
- with infection - N13.6
- Pyelitis (congenital) (uremic) - See Also: Pyelonephritis;
- with
- calculus
- with hydronephrosis - N13.6
- with hydronephrosis - N13.6
- Pyelonephritis - See Also: Nephritis, tubulo-interstitial;
- with
- calculus
- with hydronephrosis - N13.6
- with hydronephrosis - N13.6
- with hydronephrosis - N13.6
- Pyohydronephrosis - N13.6
- Pyonephrosis - N13.6
- Stricture - See Also: Stenosis;
- ureter (postoperative) - N13.5
- with
- hydronephrosis - N13.1
- with infection - N13.6
- ureterovesical orifice - N13.5
- with infection - N13.6
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
- kidney
- with calculus
- with hydronephrosis
- Angulation
- ureter
- with infection
- Calculus, calculi, calculous
- kidney (impacted) (multiple) (pelvis) (recurrent) (staghorn)
- with calculus, ureter
- with hydronephrosis
- with infection
- Calculus, calculi, calculous
- kidney (impacted) (multiple) (pelvis) (recurrent) (staghorn)
- congenital
- with hydronephrosis
- with infection
- Calculus, calculi, calculous
- pyelitis (impacted) (recurrent)
- with hydronephrosis
- Calculus, calculi, calculous
- pyelonephritis (impacted) (recurrent)
- with hydronephrosis
- Calculus, calculi, calculous
- ureter (impacted) (recurrent)
- with calculus, kidney
- with hydronephrosis
- with infection
- Calculus, calculi, calculous
- ureter (impacted) (recurrent)
- with hydronephrosis
- with infection
- Calculus, calculi, calculous
- urinary (duct) (impacted) (passage) (tract)
- with hydronephrosis
- with infection
- Constriction
- ureter
- with infection
- Contraction(s), contracture, contracted
- ureterovesical orifice (postinfectional)
- with infection
- Fasciitis
- perirenal (with ureteral obstruction)
- with infection
- Fibrosis, fibrotic
- retroperitoneal
- with infection
- Hydronephrosis(atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC
- with
- infection
- Hydronephrosis(atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC
- with
- obstruction (by) (of)
- renal calculus
- with infection
- Hydronephrosis(atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC
- with
- obstruction (by) (of)
- ureteral NEC
- with infection
- Hydronephrosis(atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC
- with
- obstruction (by) (of)
- ureteral NEC
- calculus
- with infection
- Hydronephrosis(atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC
- with
- obstruction (by) (of)
- ureteropelvic junction (congenital)
- acquired
- with infection
- Hydronephrosis(atrophic) (early) (functionless) (intermittent) (primary) (secondary) NEC
- with
- ureteral stricture NEC
- with infection
- Hydropyonephrosis
- Hydroureter
- with infection
- Infection, infected, infective(opportunistic)
- kidney (cortex) (hematogenous)
- with calculus
- with hydronephrosis
- Kink, kinking
- ureter (pelvic junction)
- with
- hydronephrosis
- with infection
- Narrowing
- ureter
- with infection
- Obliteration
- ureter
- with infection
- Obstruction, obstructed, obstructive
- ureter (functional) (pelvic junction) NEC
- with
- hydronephrosis
- with infection
- Ormond's disease(with ureteral obstruction)
- with infection
- Prolapse, prolapsed
- ureter
- with obstruction
- with infection
- Pyelitis(congenital) (uremic)
- with
- calculus
- with hydronephrosis
- Pyelitis(congenital) (uremic)
- chronic
- with calculus
- with hydronephrosis
- Pyelonephritis
- with
- calculus
- with hydronephrosis
- Pyelonephritis
- calculous
- with hydronephrosis
- Pyelonephritis
- chronic
- with calculus
- with hydronephrosis
- Pyohydronephrosis
- Pyonephrosis
- Stricture
- ureter (postoperative)
- with
- hydronephrosis
- with infection
- Stricture
- ureterovesical orifice
- with infection
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
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.Pyonephrosis
pus within the collecting system of the kidney.Chronic Pyelonephritis
persistent pyelonephritis.
Patient EducationClinical
Urinary Tract Infections
The urinary system is the body's drainage system for removing wastes and extra water. It includes two kidneys, two ureters, a bladder, and a urethra. Urinary tract infections (UTIs) are the second most common type of infection in the body.
Read the full article at MedlinePlus
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Convert N13.6 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About N13.6Overview
Is N13.6 (Obstructive and reflux uropathy) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report pyonephrosis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does N13.6 group to?
When pyonephrosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 689, 690, with relative weights from 0.8095 to 1.1603 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of N13.6?
Under the General Equivalence Mappings, pyonephrosis converts to ICD-9-CM 590.80 (pyelonephritis NOS). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
