2027 ICD-10-CM Diagnosis Code N04.B2Nephrotic syndrome with secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN)

ICD-10-CM Codes›N00–N99›N00-N08›N04

ICD-10-CM N04.B2
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

N04.B2 is a billable ICD-10-CM diagnosis code for nephrotic syndrome with secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN). It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 698 through 700. 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 286 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nephritis; nephrosis; renal sclerosis.

N04.B2 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the ESRD (V21) category 141 for payment year 2027.

Code Identity

ICD-10-CM Code
N04.B2
Billable Status
Yes — Valid for Submission
Code Describes
Nephrotic syndrome with secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN)
Short Description
Nep syn with sec imm cmplx membr prolif glomrlneph (IC-MPGN)
Parent Code
N04.B
Nephrotic syndrome with immune complex membranoproliferative glomerulonephritis (IC-MPGN)

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN00-N08Glomerular diseases
CategoryN04Nephrotic syndrome
This CodeN04.B2Nephrotic syndrome with secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN)

Medicare Risk Adjustment (HCC)Billing

N04.B2 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Other CMS Models
ESRD (V21): HCC 141
ESRD V21 weights: 0.000 dialysis, 0.000 functioning graft
Part D (RxHCC)
Not mapped
N04.B2 does not risk-adjust in the RxHCC prescription drug model

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to N04.B2: its own notes plus those printed at N04, block N00-N08, and Chapter 14. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From N04 Nephrotic syndrome applies to 16 codes
  • congenital nephrotic syndrome
  • lipoid nephrosis

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block N00-N08 Glomerular diseases applies to 107 codes
  • hypertensive chronic kidney disease (I12.-)

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.

From Chapter 14 (N00-N99) Diseases of the genitourinary system applies to 838 codes
  • 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)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From Block N00-N08 Glomerular diseases applies to 107 codes
  • any associated kidney failure (N17-N19).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name N04.B2, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming N04.B2: they are not reported together with it, unless the two conditions are unrelated.

  • Q63 Other congenital malformations of kidney
    congenital nephrotic syndrome (N04.-) names N04.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN001
Nephritis; nephrosis; renal sclerosis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Nephrotic Syndrome

    a condition characterized by severe proteinuria, greater than 3.5 g/day in an average adult. the substantial loss of protein in the urine results in complications such as hypoproteinemia; generalized edema; hypertension; and hyperlipidemias. diseases associated with nephrotic syndrome generally cause chronic kidney dysfunction.

Patient EducationClinical

Kidney Diseases

You have two kidneys, each about the size of your fist. They are near the middle of your back, just below the rib cage. Inside each kidney there are about a million tiny structures called nephrons. They filter your blood. They remove wastes and extra water, which become urine. The urine flows through tubes called ureters.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code History & ChangesHistory

Replacement N04.B2 replaces the following previously assigned code(s):

  • N04.8 - Nephrotic syndrome with other morphologic changes
FY 2026AddedAdded to the ICD-10-CM code setEffective October 1, 2025.
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About N04.B2Overview

Is N04.B2 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report nephrotic syndrome with secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN) on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does N04.B2 group to?

When nephrotic syndrome with secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN) is the principal diagnosis on an inpatient stay, it groups to MS-DRG 699, 698, 700, with relative weights from 0.6740 to 1.6400 depending on complications. Higher weights mean higher Medicare reimbursement.

Is N04.B2 a CC or MCC?

CMS lists N04.B2 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 286 closely related codes in its exclusion list.

Can N04.B2 be reported with a code from I12?

Not as a rule. The Excludes1 note at block N00-N08, which applies to N04.B2, lists "hypertensive chronic kidney disease (I12.-)". 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).

Does N04.B2 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: N04.B2 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the ESRD (V21) category 141 (Nephritis).