2027 ICD-10-CM Diagnosis Code L98.423Non-pressure chronic ulcer of back with necrosis of muscle
ICD-10-CM Codes›L00–L99›L80-L99›L98
- Billable — Valid for Submission
- Risk Adjusts — HCC 380
- Chronic Condition
L98.423 is a billable ICD-10-CM diagnosis code for non-pressure chronic ulcer of back with necrosis of muscle. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 573 through 575, 592 through 594. Coders also document this condition as chronic ulcer of back. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Non-pressure ulcer of skin.
For Medicare Advantage risk adjustment, L98.423 maps to CMS-HCC Category 380 (Chronic Ulcer of Skin, Except Pressure, Through to Bone or Muscle) under the V28 model, adding a risk factor of about 1.078 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
L98.423 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
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.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chronic ulcer of back
- Chronic ulcer of sacral region
- Necrosis of sacral muscle co-occurrent and due to chronic ulcer of sacrum
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to L98.423: its own notes plus those printed at L98.4 and Chapter 12. A note printed at a category, block or chapter applies to every code under it.
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.
- 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)
- lipomelanotic reticulosis (I89.8)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- systemic connective tissue disorders (M30-M36)
- viral warts (B07.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name L98.423, its category, or a range that includes it.
Use Additional Code 6
These codes say to use an additional code from the note, and L98.423 is one of the codes named.
- T65.84 Toxic effect of xylazinenon-pressure chronic ulcer of skin, not elsewhere classified (L98.4-) names L98.4-, which includes this code
- E08.622 Diabetes mellitus due to underlying condition with other skin ulcer
- E09.622 Drug or chemical induced diabetes mellitus with other skin ulcer
- E10.622 Type 1 diabetes mellitus with other skin ulcer
- E11.622 Type 2 diabetes mellitus with other skin ulcer
- E13.622 Other specified diabetes mellitus with other skin ulcer
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.
Patient EducationClinical
Skin Conditions
Your skin is your body's largest organ. It covers the entire outside of your body. There are many ways that your skin protects your body and helps keep you healthy. For example, it:
The full article covers:
- What does your skin do?
- What problems and conditions can affect your skin?
- How can I keep my skin healthy?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert L98.423 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About L98.423Overview
What is the ICD-10 code for non-pressure chronic ulcer of back with necrosis of muscle?
The ICD-10-CM code for non-pressure chronic ulcer of back with necrosis of muscle is L98.423 (sometimes written as L98423). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is L98.423 (Non-pressure chronic ulcer of back) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report non-pressure chronic ulcer of back with necrosis of muscle on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does L98.423 group to?
When non-pressure chronic ulcer of back with necrosis of muscle is the principal diagnosis on an inpatient stay, it groups to MS-DRG 592, 573, 574, 575, 593, 594, with relative weights from 0.7347 to 6.3547 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of L98.423?
Under the General Equivalence Mappings, non-pressure chronic ulcer of back with necrosis of muscle converts to ICD-9-CM 707.8 (chronic skin ulcer NEC). The mapping is approximate, so confirm the match fits the documentation.
What HCC is L98.423?
L98.423 (non-pressure chronic ulcer of back with necrosis of muscle) maps to CMS-HCC Category 380 (Chronic Ulcer of Skin, Except Pressure, Through to Bone or Muscle), commonly written as HCC 380, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 161 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 311.
Does L98.423 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, L98.423 adds a risk adjustment factor of about 1.078 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.839 to 1.422 depending on the payment segment). A more severe related category (HCC 379) supersedes it when both are reported. See the full factor table on the HCC 380 category page.
