ICD-10 N05.A
Billable / Specific CCUnspecified nephritic syndrome with C3 glomerulonephritis
About ICD-10-CM N05.A
ICD-10-CM code N05.A represents Unspecified nephritic syndrome with C3 glomerulonephritis. This is a billable/specific code in the Genitourinary System chapter (block N05). The 2026 edition of ICD-10-CM N05.A became effective on October 1, 2025.
Coding Tips for N05.A
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
N05.A 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 N05.A. Per CMS ICD-10-CM Tabular 2026.
- Unspecified nephritic syndrome with C3 glomerulopathy
Type 1 Excludes
Pure excludes, these codes can never be coded together with N05.A. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- Unspecified nephritic syndrome (with C3 glomerulopathy) with dense deposit disease (N05.6)
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Unspecified nephritic syndrome with C3 glomerulonephritis. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for N05.A
Local Coverage Determinations (LCDs) from CMS MACs that list N05.A as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing N05.A.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but N05.A doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with N05.A
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To N05.A
Other codes in section N00-N08 (Glomerular diseases).
ICD-10 N05.A, Billing FAQ
Is ICD-10 code N05.A billable? +
Yes, N05.A 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 N05.A? +
ICD-10 N05.A includes: Unspecified nephritic syndrome with C3 glomerulopathy.
What codes are Type 1 Excludes for N05.A? +
Type 1 Excludes (never code together with N05.A): Unspecified nephritic syndrome (with C3 glomerulopathy) with dense deposit disease (N05.6)
Is N05.A 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.
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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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