ICD-10-CM 2027
ICD-10 code for chronic pyelitis
Chronic tubulo-interstitial nephritis, unspecified
From the official ICD-10-CM alphabetic index entry “Pyelitis (congenital) (uremic) › chronic”. Page updated September 29, 2026.
About coding chronic pyelitis
The ICD-10-CM code for chronic pyelitis is N11.9 (Chronic tubulo-interstitial nephritis, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on N11.9.
Within N11, choose N11.9 (unspecified) only when documentation doesn't support a more specific option: nonobstructive reflux-associated chronic pyelonephritis (N11.0), chronic obstructive pyelonephritis (N11.1) and other chronic tubulo-interstitial nephritis (N11.8).
Use an additional code (B95-B97), to identify infectious agent.
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
More specific chronic pyelitis codes (official index)
- with calculus
- with hydronephrosis N13.6 — Pyonephrosis
Common questions about chronic pyelitis ICD-10 codes
What is the ICD-10 code for chronic pyelitis?
- N11.9 — Chronic tubulo-interstitial nephritis, unspecified. More specific codes apply when the documentation supports them: N13.6.
Is N11.9 billable?
- Yes. N11.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N11.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N11.9 as a principal diagnosis.
Is N11.9 a CC or MCC?
- N11.9 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.