What is ICD-10 code J4A.8?

J4A.8 is the ICD-10-CM diagnosis code for Other chronic lung allograft dysfunction. It belongs to the ICD-10-CM chapter for diseases of the respiratory system (j00-j99). J4A.8 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. J4A.8 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. J4A.8 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. J4A.8 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for J4A.8?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For J4A.8, V28 maps to Lung Transplant Status/Complications at RAF 0.193 while V24 mapped to Major Organ Transplant or Replacement Status at RAF 0.910. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting J4A.8?

Use this code only after other specific chronic lung allograft dysfunction codes (J4A.0-J4A.7) have been ruled out or are not applicable Ensure documentation clearly indicates the dysfunction is chronic (long-term) rather than acute, and that it is related to a lung transplant Because J4A.8 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

J4A.8 ICD-10 Code: Other chronic lung allograft

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupJ4A.8Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the respiratory system (J00-J99) / Chronic lower respiratory diseases (J40-J4A)

J4A.8

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Other chronic lung allograft dysfunction

This code describes a chronic condition where a transplanted lung is not functioning properly due to reasons other than the more common types of rejection or infection. It represents long-term problems with how well the transplanted lung works after surgery.

Buddy Insight

Other chronic lung allograft dysfunction captures CLAD presentations that do not fit the classic restrictive allograft syndrome or bronchiolitis obliterans syndrome patterns.

CMS-HCC V28

Mapped

HCC 276

Lung Transplant Status/Compli...

RAF 0.193

CMS-HCC V24

Mapped

HCC 186

Major Organ Transplant or Rep...

RAF 0.910

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 186

Major Organ Transplant or Rep...

RAF 0.0

RXHCC

Mapped

HCC 396

Allograft Complications

RAF 0.0

Code Trumping

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Code Book Path

Official

J4AChronic lung allograft dysfunction

J4A.8Other chronic lung allograft dysfunction

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for J4A.8 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for J4A.8 in this effective period.

Related Child Codes

Official

J4A.0Restrictive allograft syndrome

J4A.9Chronic lung allograft dysfunction, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for J4A.8 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for J4A.8 in this effective period.

Code First

Official

, if applicable:
heart-lung transplant rejection (T86.31)
lung transplant rejection (T86.810)
other complications of heart-lung transplant (T86.39)
other complications of lung transplant (T86.818)

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for J4A.8 in this effective period.

Code Also

Official

, if applicable, bronchiolitis obliterans syndrome (J44.81)

Buddy Documentation Tip

HCC Buddy guidance

Lung transplant history with date of transplantation

Documentation of chronic lung allograft dysfunction that does not meet criteria for RAS or BOS

Pulmonary function testing showing persistent decline from post-transplant baseline

Imaging findings supporting chronic allograft changes

MEAT Support

HCC Buddy guidance

Lung transplant history with date of transplantation

Documentation of chronic lung allograft dysfunction that does not meet criteria for RAS or BOS

Pulmonary function testing showing persistent decline from post-transplant baseline

Imaging findings supporting chronic allograft changes

Audit Caution

HCC Buddy guidance

Using this code when documentation clearly describes RAS (J4A.0) or BOS (J44.81)

Not coding lung transplant status (Z94.2) as an additional diagnosis

Confusing chronic allograft dysfunction with acute rejection — different treatment and prognosis

Failing to recognize the high V24 RAF weight (0.91) which makes accurate post-transplant coding critical

Common Mistakes

HCC Buddy guidance

J4A.0 — Restrictive allograft syndrome: use when restrictive pattern is specifically documented

J4A.9 — Chronic lung allograft dysfunction, unspecified: use when the type cannot be determined

J44.81 — Bronchiolitis obliterans syndrome: use when obstructive pattern is documented

T86.810 — Lung transplant rejection: use for acute rejection episodes

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is J4A.8 an HCC code?

Yes. J4A.8 maps to Lung Transplant Status/Complications under the CMS-HCC V28 risk adjustment model (and Major Organ Transplant or Replacement Status under V24).

HCC Category Mapping

V28HCC 276, Lung Transplant Status/Complications

0.193

V24HCC 186, Major Organ Transplant or Replacement Status

0.910

ESRDHCC 186, Major Organ Transplant or Replacement Status

0.000

RxHCCHCC 396, Allograft Complications

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for J4A.8

For J4A.8to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed J4A.8 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

J4A.8 is the ICD-10-CM diagnosis code for other chronic lung allograft dysfunction. This code describes a chronic condition where a transplanted lung is not functioning properly due to reasons other than the more common types of rejection or infection. It represents long-term problems with how well the transplanted lung works after surgery. J4A.8 sits in the ICD-10-CM chapter for diseases of the respiratory system (j00-j99), within the section covering chronic lower respiratory diseases (j40-j4a).

Under the CMS-HCC V28 risk adjustment model, J4A.8 maps to Lung Transplant Status/Complications (HCC 276) with a community, non-dual, aged base RAF weight of 0.193. Under the older CMS-HCC V24 model, J4A.8 maps to Major Organ Transplant or Replacement Status (HCC 186) with a community, non-dual, aged base RAF weight of 0.910. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Use this code only after other specific chronic lung allograft dysfunction codes (J4A.0-J4A.7) have been ruled out or are not applicable. Because J4A.8 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for J4A.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code only after other specific chronic lung allograft dysfunction codes (J4A.0-J4A.7) have been ruled out or are not applicable
•Ensure documentation clearly indicates the dysfunction is chronic (long-term) rather than acute, and that it is related to a lung transplant

Clinical Significance

Other chronic lung allograft dysfunction captures CLAD presentations that do not fit the classic restrictive allograft syndrome or bronchiolitis obliterans syndrome patterns. These may include mixed phenotypes or evolving forms of chronic rejection following lung transplantation, all carrying significant clinical implications for transplant recipients.

Documentation Requirements

✓Lung transplant history with date of transplantation
✓Documentation of chronic lung allograft dysfunction that does not meet criteria for RAS or BOS
✓Pulmonary function testing showing persistent decline from post-transplant baseline
✓Imaging findings supporting chronic allograft changes
✓Immunosuppression management details
✓Differentiation from acute rejection and other post-transplant complications

Commonly Confused Codes

•J4A.0: Restrictive allograft syndrome: use when restrictive pattern is specifically documented
•J4A.9: Chronic lung allograft dysfunction, unspecified: use when the type cannot be determined
•J44.81: Bronchiolitis obliterans syndrome: use when obstructive pattern is documented
•T86.810: Lung transplant rejection: use for acute rejection episodes
•Z94.2: Lung transplant status: code additionally