2026 ICD-10-CM Diagnosis Code J99Respiratory disorders in diseases classified elsewhere
J99 is a billable ICD-10-CM diagnosis code for respiratory disorders in diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 196 through 198. The code is a manifestation code that cannot be reported as the principal diagnosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified lower respiratory disease.
For Medicare Advantage risk adjustment, J99 maps to CMS-HCC Category 280 (Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders) under the V28 model, adding a risk factor of about 0.319 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for J99.
Medicare Risk Adjustment (HCC)Billing
J99 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.
- Acute pulmonary African histoplasmosis
- Acute pulmonary histoplasmosis
- African histoplasmosis
- Allergic disorder of respiratory system
- Chronic pulmonary African histoplasmosis
- Chronic pulmonary histoplasmosis
- Disorder of respiratory system co-occurrent with human immunodeficiency virus infection
- Disorder of respiratory system due to microscopic polyangiitis
- Lung disease due to connective tissue disorder
- Lung involvement associated with another disorder
- Necrosis of artery
- Pneumonia caused by Histoplasma
- Pneumonia caused by Histoplasma capsulatum
- Pulmonary African histoplasmosis
- Pulmonary amyloidosis
- Pulmonary histoplasmosis
- Pulmonary schistosomiasis
- Respiratory disorder with AIDS
- Restrictive lung disease
- Restrictive lung disease due to amyotrophic lateral sclerosis
- Restrictive lung disease due to Parkinson disease
- Restrictive lung mechanics due to neuromuscular disease
- Vasculitis due to systemic disease
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code First
- underlying disease, such as:
- amyloidosis E85
- ankylosing spondylitis M45
- congenital syphilis A50
- cryoglobulinemia D89.1
- early congenital syphilis A50.0
- plasminogen deficiency E88.02
- schistosomiasis B65.0 B65.9
Type 1 Excludes
- respiratory disorders in:
- amebiasis A06.5
- blastomycosis B40.0 B40.2
- candidiasis B37.1
- coccidioidomycosis B38.0 B38.2
- cystic fibrosis with pulmonary manifestations E84.0
- dermatomyositis M33.01 M33.11
- histoplasmosis B39.0 B39.2
- late syphilis A52.72 A52.73
- polymyositis M33.21
- Sjögren syndrome M35.02
- systemic lupus erythematosus M32.13
- systemic sclerosis M34.81
- Wegener's granulomatosis M31.30 M31.31
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Restrictive Lung Disease
decreased lung volume and inadequate ventilation due to parenchymal lung disorders (e.g., interstitial pulmonary fibrosis) or extrapulmonary disorders (e.g., scoliosis). patients present with shortness of breath and cough.
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
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Convert J99 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About J99Overview
What is the ICD-10 code for respiratory disorders in diseases classified elsewhere?
The ICD-10-CM code for respiratory disorders in diseases classified elsewhere is J99. It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is J99 (Respiratory disorders in diseases classified elsewhere) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report respiratory disorders in diseases classified elsewhere on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does J99 group to?
On inpatient claims, respiratory disorders in diseases classified elsewhere maps to MS-DRG 196, 197, 198, with relative weights from 0.7162 to 1.8872 depending on complications. Higher weights mean higher Medicare reimbursement.
Can J99 be a principal diagnosis?
No. This is a manifestation code: respiratory disorders in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
What is the ICD-9 equivalent of J99?
Under the General Equivalence Mappings, respiratory disorders in diseases classified elsewhere converts to ICD-9-CM 517.8 (lung involv in oth dis). The mapping is approximate, so confirm the match fits the documentation.
What HCC is J99?
J99 (respiratory disorders in diseases classified elsewhere) maps to CMS-HCC Category 280 (Chronic Obstructive Pulmonary Disease, Interstitial Lung Disorders, and Other Chronic Lung Disorders), commonly written as HCC 280, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 112 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 J99 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, J99 adds a risk adjustment factor of about 0.319 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.209 to 0.390 depending on the payment segment). A more severe related category (HCC 276, HCC 277, HCC 278, and HCC 279) supersedes it when both are reported. See the full factor table on the HCC 280 category page.
