2027 ICD-10-CM Diagnosis Code N13.6Pyonephrosis
ICD-10-CM Codes›N00–N99›N10-N16›N13
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
N13.6 is a billable ICD-10-CM diagnosis code for pyonephrosis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 689 through 690, 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. 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 pyelonephritis
- Recurrent urinary tract infection
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to N13.6: its own notes plus those printed at N13, block N10-N16, and Chapter 14. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- pyeloureteritis cystica (N28.85)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name N13.6, its category, or a range that includes it.
Excludes1 8
These codes carry an Excludes1 note naming N13.6: they are not reported together with it, unless the two conditions are unrelated.
- M72.8 Other fibroblastic disordersperirenal fasciitis with infection (N13.6)
- N13.1 Hydronephrosis with ureteral stricture, not elsewhere classifiedHydronephrosis with ureteral stricture with infection (N13.6)
- N13.2 Hydronephrosis with renal and ureteral calculous obstructionHydronephrosis with renal and ureteral calculous obstruction with infection (N13.6)
- N13.3 Other and unspecified hydronephrosishydronephrosis with infection (N13.6)
- N13.4 Hydroureterhydroureter with infection (N13.6)
- N13.5 Crossing vessel and stricture of ureter without hydronephrosisCrossing vessel and stricture of ureter without hydronephrosis with infection (N13.6)
- N39.0 Urinary tract infection, site not specifiedpyonephrosis (N13.6)
- N11.1 Chronic obstructive pyelonephritisobstructive uropathy (N13.-) names N13.-, which includes this code
Code Also 3
These codes say N13.6 may also be needed to fully describe the condition. The note gives no sequencing direction.
- N80.A4 Superficial endometriosis of ureterif applicable, obstructive and reflux uropathy (N13.-) names N13.-, which includes this code
- N80.A5 Deep endometriosis of ureterif applicable, obstructive and reflux uropathy (N13.-) names N13.-, which includes this code
- N80.A6 Endometriosis of ureter, unspecified depthif applicable, obstructive and reflux uropathy (N13.-) names N13.-, which includes this 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 infection N13.6
Constriction See Also: Stricture;
with infection N13.6
Hydropyonephrosis N13.6
Hydroureter See Also: Hydronephrosis; N13.4
with infection N13.6
Narrowing See Also: Stenosis;
with infection N13.6
Pyelitis (congenital) (uremic) See Also: Pyelonephritis;
calculus See: category N20;
with hydronephrosis N13.6
with calculus See: category N20;
with hydronephrosis N13.6
Pyelonephritis See Also: Nephritis, tubulo-interstitial;
calculus See: category N20;
with hydronephrosis N13.6
calculous See: category N20;
with hydronephrosis N13.6
with calculus See: category N20;
with hydronephrosis N13.6
Pyohydronephrosis N13.6
Pyonephrosis N13.6
Stricture See Also: Stenosis;
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.
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
What is the ICD-10 code for pyonephrosis?
The ICD-10-CM code for pyonephrosis is N13.6 (sometimes written as N136). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
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, 2026 through September 30, 2027.
What MS-DRG does N13.6 group to?
When pyonephrosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 689, 690, with relative weights from 0.8008 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is N13.6 a CC or MCC?
CMS lists N13.6 as a CC (complication or comorbidity) for FY 2027. 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.
Can N13.6 be reported with N28.85?
Not as a rule. The Excludes1 note at block N10-N16, which applies to N13.6, lists "pyeloureteritis cystica (N28.85)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
