ICD-10 N11.9
Billable / Specific CCChronic tubulo-interstitial nephritis, unspecified
About ICD-10-CM N11.9
ICD-10-CM code N11.9 represents Chronic tubulo-interstitial nephritis, unspecified. This is a billable/specific code in the Genitourinary System chapter (block N11). The 2026 edition of ICD-10-CM N11.9 became effective on October 1, 2025.
Coding Tips for N11.9
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
N11.9 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under N11.9. Per CMS ICD-10-CM Tabular 2026.
- Chronic interstitial nephritis NOS
- Chronic pyelitis NOS
- Chronic pyelonephritis NOS
Inpatient DRG Impact, CC
1328:228 codes Chronic tubulo-interstitial nephritis, unspecified. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for N11.9
Local Coverage Determinations (LCDs) from CMS MACs that list N11.9 as a covered diagnosis.
Showing top 10 of 12 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing N11.9.
2 Medicare
CPT Codes Commonly Billed with N11.9
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 81001 Urinalysis with microscopy — UTI, cystitis, dysuria, urinary frequency, abnormal urine, pyelonephritis, chronic pyelonephritis, fever, kidney stone Laboratory
Convert N11.9 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| N11.9 | 59080 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To N11.9
Other codes in section N10-N16 (Renal tubulo-interstitial diseases).
ICD-10 N11.9, Billing FAQ
Is ICD-10 code N11.9 billable? +
Yes, N11.9 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to N11.9? +
ICD-10 N11.9 includes: Chronic interstitial nephritis NOS; Chronic pyelitis NOS; Chronic pyelonephritis NOS.
Is N11.9 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with N11.9? +
Procedures frequently paired with N11.9 include: 81001.
What ICD-9 codes does N11.9 map to? +
Per CMS GEMs, N11.9 maps to ICD-9 codes: 59080. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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