2026 ICD-10-CM Diagnosis Code M34.1CR(E)ST syndrome
ICD-10-CM Codes›M00–M99›M30-M36›M34
- Billable — Valid for Submission
- Risk Adjusts — HCC 93
- Chronic Condition
M34.1 is a billable ICD-10-CM diagnosis code for CR(E)ST syndrome. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 545 through 547. Coders also document this condition as CREST syndrome. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Systemic lupus erythematosus and connective tissue disorders.
For Medicare Advantage risk adjustment, M34.1 maps to CMS-HCC Category 93 (Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders) under the V28 model, adding a risk factor of about 0.617 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
M34.1 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 2026.
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.
- CREST syndrome
- CRST syndrome
- Limited systemic sclerosis
- Raynaud's phenomenon
- Secondary Raynaud's phenomenon
- Systemic sclerosis with limited cutaneous involvement
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Combination of calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, telangiectasia
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
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
CREST Syndrome
a mild form of limited scleroderma, a multi-system disorder. its features include symptoms of calcinosis; raynaud disease; esophageal motility disorders; sclerodactyly, and telangiectasis. when the defect in esophageal function is not prominent, it is known as crst syndrome.
Patient EducationClinical
Scleroderma
Scleroderma means "hard skin." It's the name of an autoimmune disease that causes inflammation and thickening in the skin and other areas of the body. This inflammation causes you to have areas of tight, hard skin. Scleroderma may affect just one area of your body, or it can affect many systems in your body.
The full article covers:
- What is scleroderma?
- What are the types of scleroderma?
- What causes scleroderma?
- Who is more likely to develop scleroderma?
- What are the symptoms of scleroderma?
- How is scleroderma diagnosed?
- What are the treatments for scleroderma?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M34.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M34.1Overview
What is the ICD-10 code for CR(E)ST syndrome?
The ICD-10-CM code for CR(E)ST syndrome is M34.1 (sometimes written as M341). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is M34.1 (Systemic sclerosis [scleroderma]) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report CR(E)ST syndrome on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M34.1 group to?
When CR(E)ST syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 545, 546, 547, with relative weights from 0.8362 to 2.4817 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of M34.1?
Under the General Equivalence Mappings, CR(E)ST syndrome converts to ICD-9-CM 710.1 (systemic sclerosis). The mapping is approximate, so confirm the match fits the documentation.
What HCC is M34.1?
M34.1 (CR(E)ST syndrome) maps to CMS-HCC Category 93 (Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders), commonly written as HCC 93, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 40 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 82.
Does M34.1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, M34.1 adds a risk adjustment factor of about 0.617 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.288 to 0.617 depending on the payment segment). HCC 93 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 93 category page.
