2026 ICD-10-CM Diagnosis Code M32.13Lung involvement in systemic lupus erythematosus
ICD-10-CM Codes›M00–M99›M30-M36›SLE
- Billable — Valid for Submission
- Risk Adjusts — HCC 94
- Chronic Condition
M32.13 is a billable ICD-10-CM diagnosis code for lung involvement in systemic lupus erythematosus. 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 lung disease due to connective tissue disorder. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Systemic lupus erythematosus and connective tissue disorders.
For Medicare Advantage risk adjustment, M32.13 maps to CMS-HCC Category 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders) under the V28 model, adding a risk factor of about 0.268 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
M32.13 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.
- Lung disease due to connective tissue disorder
- Lung disease with systemic lupus erythematosus
- Lung disorder due to autoimmune disorder
- Lupus disease of the lung
- Lupus pneumonitis
- Shrinking lung syndrome
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Pleural effusion due to systemic lupus erythematosus
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.
Disease, diseased See Also: Syndrome;
lupus erythematosus M32.13
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Lung Diseases
When you breathe, your lungs take in oxygen from the air and deliver it to the bloodstream. The cells in your body need oxygen to work and grow. During a normal day, you breathe nearly 25,000 times. People with lung disease have difficulty breathing. Millions of people in the U.S. have lung disease.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M32.13 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M32.13Overview
What is the ICD-10 code for lung involvement in systemic lupus erythematosus?
The ICD-10-CM code for lung involvement in systemic lupus erythematosus is M32.13 (sometimes written as M3213). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is M32.13 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report lung involvement in systemic lupus erythematosus on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M32.13 group to?
When lung involvement in systemic lupus erythematosus 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 M32.13?
Under the General Equivalence Mappings, lung involvement in systemic lupus erythematosus converts to ICD-9-CM 710.0 (syst lupus erythematosus) and 517.8 (lung involv in oth dis). The mapping is approximate, so confirm the match fits the documentation.
What HCC is M32.13?
M32.13 (lung involvement in systemic lupus erythematosus) maps to CMS-HCC Category 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders), commonly written as HCC 94, 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 227.
Does M32.13 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, M32.13 adds a risk adjustment factor of about 0.268 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.196 to 0.297 depending on the payment segment). A more severe related category (HCC 93) supersedes it when both are reported. See the full factor table on the HCC 94 category page.
