N05.5 ICD-10-CM Code: Unspecified nephritic syndrome with diffuse mesangiocapillary glomerulonephritis
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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Glomerular diseases (N00-N08)
N05.5
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceUnspecified nephritic syndrome with diffuse mesangiocapillary glomerulonephritis
A kidney disease characterized by inflammation and protein in the urine, with a specific type of glomerular damage called diffuse mesangiocapillary glomerulonephritis affecting the filtering units of the kidneys.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
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Code Book Path
Inclusion Terms
Official- Unspecified nephritic syndrome with membranoproliferative glomerulonephritis, types 1 and 3, or NOS
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for N05.5 in this effective period.
Related Child Codes
Includes
Official- glomerular disease NOS
- glomerulonephritis NOS
- nephritis NOS
- nephropathy NOS and renal disease NOS with morphological lesion specified in .0-.8
Excludes 1
Official- Unspecified nephritic syndrome with C3 glomerulonephritis (N05.A)
- Unspecified nephritic syndrome with C3 glomerulopathy (N05.A)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for N05.5 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for N05.5 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for N05.5 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is N05.5 an HCC code?
No. N05.5 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
N05.5 is the ICD-10-CM diagnosis code for unspecified nephritic syndrome with diffuse mesangiocapillary glomerulonephritis. A kidney disease characterized by inflammation and protein in the urine, with a specific type of glomerular damage called diffuse mesangiocapillary glomerulonephritis affecting the filtering units of the kidneys. N05.5 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering glomerular diseases (n00-n08).
N05.5 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This code specifies the morphologic pattern of glomerulonephritis; ensure pathology reports confirm mesangiocapillary changes before coding.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N05.5 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code specifies the morphologic pattern of glomerulonephritis; ensure pathology reports confirm mesangiocapillary changes before coding
- •N05.5 is used when the nephritic syndrome is unspecified but the glomerular pathology is identified as mesangiocapillary