2026 ICD-10-CM Diagnosis Code N17.1Acute kidney failure with acute cortical necrosis
ICD-10-CM Codes›N00–N99›N17-N19›N17
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Not Chronic
N17.1 is a billable ICD-10-CM diagnosis code for acute kidney failure with acute cortical necrosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 673 through 675, 682 through 684, 791, 793. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 301 closely related codes. Coders also document this condition as acute renal cortical necrosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute and unspecified renal failure.
N17.1 no longer risk-adjusts for Medicare Advantage: it mapped to HCC 135 under the retired CMS-HCC V24 model through payment year 2025 but maps to no category in the live V28 model. It still risk-adjusts in the PACE (CMS-HCC V22) category 135, ESRD (V21) category 135, and ESRD (V24) category 135 for payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
N17.1 no longer risk-adjusts for Medicare Advantage: it maps to no payment category in the live CMS-HCC V28 model, although it still risk-adjusts in the other CMS models shown below.
Source: CMS Payment Year 2026 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.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute renal cortical necrosis
- Acute renal failure due to acute cortical necrosis
- Renal cortical necrosis
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Acute cortical necrosis
- Cortical necrosis NOS
- Renal cortical necrosis
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Necrosis, necrotic (ischemic) See Also: Gangrene;
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Kidney Failure
Healthy kidneys clean your blood by removing excess fluid, minerals, and wastes. They also make hormones that keep your bones strong and your blood healthy. But if the kidneys are damaged, they don't work properly. Harmful wastes can build up in your body. Your blood pressure may rise.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert N17.1 to ICD-9-CMHistory
Code HistoryHistory
Questions About N17.1Overview
What is the ICD-10 code for acute kidney failure with acute cortical necrosis?
The ICD-10-CM code for acute kidney failure with acute cortical necrosis is N17.1 (sometimes written as N171). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is N17.1 (Acute kidney failure) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report acute kidney failure with acute cortical necrosis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does N17.1 group to?
When acute kidney failure with acute cortical necrosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 673, 674, 675, 682, 683, 684, 791, 793, with relative weights from 0.6003 to 4.2016 depending on complications. Higher weights mean higher Medicare reimbursement.
Is N17.1 a CC or MCC?
CMS lists N17.1 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 301 closely related codes in its exclusion list.
What is the ICD-9 equivalent of N17.1?
Under the General Equivalence Mappings, acute kidney failure with acute cortical necrosis converts to ICD-9-CM 583.6 (renal cort necrosis NOS) and 584.6 (ac kidny fail, cort necr). The mapping is approximate, so confirm the match fits the documentation.
Does N17.1 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage. N17.1 mapped to HCC 135 in the retired CMS-HCC V24 model, which last determined payment in 2025, but it maps to no category in the live V28 model; see all codes that no longer risk-adjust. It still risk-adjusts in the PACE (CMS-HCC V22) category 135 (Acute Renal Failure), ESRD (V21) category 135 (Acute Renal Failure), and ESRD (V24) category 135 (Acute Renal Failure).
