ICD-10-CM 2027
ICD-10 code for acute nephritis
Acute nephritic syndrome with unspecified morphologic changes
From the official ICD-10-CM alphabetic index entry “Nephritis, nephritic (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic) › acute”. Page updated September 29, 2026.
About coding acute nephritis
The ICD-10-CM code for acute nephritis is N00.9 (Acute nephritic syndrome with unspecified morphologic changes). The official index lists 14 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on N00.9.
Within N00, choose N00.9 (with unspecified morphologic changes) only when documentation doesn't support a more specific option: with minor glomerular abnormality (N00.0), with focal and segmental glomerular lesions (N00.1), with diffuse membranous glomerulonephritis (N00.2), with diffuse mesangial proliferative glomerulonephritis (N00.3), with diffuse endocapillary proliferative glomerulonephritis (N00.4), with diffuse mesangiocapillary glomerulonephritis (N00.5), with dense deposit disease (N00.6), with diffuse crescentic glomerulonephritis (N00.7) and 3 more.
As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 698 (Other Kidney and Urinary Tract Diagnoses with MCC, relative weight 1.6398), DRG 699 (Other Kidney and Urinary Tract Diagnoses with CC, relative weight 1.0003), DRG 700 (Other Kidney and Urinary Tract Diagnoses without CC/MCC, relative weight 0.6741), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 11 (Diseases and Disorders of the Kidney and Urinary Tract) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific acute nephritis codes (official index)
- with
- C3
- glomerulonephritis N00.A — Acute nephritic syndrome with C3 glomerulonephritis
- glomerulopathy N00.A — Acute nephritic syndrome with C3 glomerulonephritis
- with dense deposit disease N00.6 — Acute nephritic syndrome with dense deposit disease
- dense deposit disease N00.6 — Acute nephritic syndrome with dense deposit disease
- diffuse
- crescentic glomerulonephritis N00.7 — Acute nephritic syndrome with diffuse crescentic glomerulonephritis
- endocapillary proliferative glomerulonephritis N00.4 — Acute nephritic syndrome with diffuse endocapillary proliferative glomerulonephritis
- membranous glomerulonephritis N00.2 — Acute nephritic syndrome with diffuse membranous glomerulonephritis
- mesangial proliferative glomerulonephritis N00.3 — Acute nephritic syndrome with diffuse mesangial proliferative glomerulonephritis
- mesangiocapillary glomerulonephritis N00.5 — Acute nephritic syndrome with diffuse mesangiocapillary glomerulonephritis
- focal and segmental glomerular lesions N00.1 — Acute nephritic syndrome with focal and segmental glomerular lesions
- idiopathic immune membranoproliferative glomerulonephritis (IC-MPGN) N00.B1 — Acute nephritic syndrome with idiopathic immune membranoproliferative glomerulonephritis (IC-MPGN)
- secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN) N00.B2 — Acute nephritic syndrome with secondary immune complex membranoproliferative glomerulonephritis (IC-MPGN)
- minor glomerular abnormality N00.0 — Acute nephritic syndrome with minor glomerular abnormality
- specified morphological changes NEC N00.8 — Acute nephritic syndrome with other morphologic changes
Common questions about acute nephritis ICD-10 codes
What is the ICD-10 code for acute nephritis?
- N00.9 — Acute nephritic syndrome with unspecified morphologic changes. More specific codes apply when the documentation supports them: N00.A, N00.A, N00.6, N00.6 and others below.
Is N00.9 billable?
- Yes. N00.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N00.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N00.9 as a principal diagnosis.
Is N00.9 a CC or MCC?
- N00.9 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.