J91.0 ICD-10-CM Code: Malignant pleural effusion
J91.0 maps to CMS-HCC V28 17. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Diseases of the respiratory system (J00-J99) / Other diseases of the pleura (J90-J94)
J91.0
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMalignant pleural effusion
This is a buildup of fluid around the lungs caused by cancer that has spread to the lining of the lungs. The fluid accumulation can make it difficult to breathe and requires medical treatment.
Buddy Insight
Malignant pleural effusion indicates fluid accumulation in the pleural space caused by cancer, most commonly lung cancer, breast cancer, or lymphoma.
CMS-HCC V28
MappedHCC 17
Coefficient HCC 17: 4.209 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for J91.0. Check the code and parent instructions in the Code Book.
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from J00-J99, J91
- certain infectious and parasitic diseases (A00-B99)Inherited from J00-J99, J91
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from J00-J99, J91
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from J00-J99, J91
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from J00-J99, J91
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from J00-J99, J91
- neoplasms (C00-D49)Inherited from J00-J99, J91
- smoke inhalation (T59.81-)Inherited from J00-J99, J91
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from J00-J99, J91
- pleural effusion in heart failure (I50.-)Inherited from J00-J99, J91
- pleural effusion in systemic lupus erythematosus (M32.13)Inherited from J00-J99, J91
Related Codes
Includes
OfficialNo Includes notes are included in this display for J91.0. Check the code and parent instructions in the Code Book.
Excludes 1
OfficialNo Excludes 1 notes are included in this display for J91.0. Check the code and parent instructions in the Code Book.
Code First
Official- underlying neoplasm (C00-D49)
Use Additional
Official- code, where applicable, to identify:Inherited from J00-J99
- exposure to environmental tobacco smoke (Z77.22)Inherited from J00-J99
- exposure to tobacco smoke in the perinatal period (P96.81)Inherited from J00-J99
- history of tobacco dependence (Z87.891)Inherited from J00-J99
- occupational exposure to environmental tobacco smoke (Z57.31)Inherited from J00-J99
- tobacco dependence (F17.-)Inherited from J00-J99
- tobacco use (Z72.0)Inherited from J00-J99
Code Also
OfficialNo Code Also instructions are included in this display for J91.0. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is J91.0 an HCC code?
Yes. J91.0 (Malignant pleural effusion) maps to HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 4.209. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: J91.0 is billable and maps to V28 HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- J91.0
- Description
- Malignant pleural effusion
- HCC (V28)
- HCC 17 — Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
- RAF reference coefficient
- 4.209
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work J91.0 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for J91.0
For J91.0, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
J91.0 is the ICD-10-CM diagnosis code for malignant pleural effusion. This is a buildup of fluid around the lungs caused by cancer that has spread to the lining of the lungs. The fluid accumulation can make it difficult to breathe and requires medical treatment. J91.0 sits in the ICD-10-CM chapter for diseases of the respiratory system (j00-j99), within the section covering other diseases of the pleura (j90-j94).
Under the CMS-HCC V28 risk adjustment model, J91.0 maps to Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic (HCC 17) with a source-labeled community, non-dual, aged reference coefficient of 4.209. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Always verify the underlying malignancy and code it separately, as J91.0 specifically indicates the pleural effusion is related to cancer. For J91.0, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for J91.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always verify the underlying malignancy and code it separately, as J91.0 specifically indicates the pleural effusion is related to cancer
- •Ensure documentation clearly states the effusion is malignant (cancer-related) rather than benign to distinguish from other pleural effusion codes like J91.8
Clinical Significance
Malignant pleural effusion indicates fluid accumulation in the pleural space caused by cancer, most commonly lung cancer, breast cancer, or lymphoma. This is a marker of advanced/metastatic disease and carries a poor prognosis with median survival of 3-12 months. Accurate coding is critical because it captures the severity of the underlying malignancy and the palliative care resource burden including repeated thoracentesis and possible pleurodesis.
Documentation Requirements
- ✓Documentation that the pleural effusion is malignant (positive cytology, known pleural metastases, or clinical determination by the treating oncologist)
- ✓Identification and coding of the underlying primary malignancy as a separate diagnosis
- ✓Pleural fluid cytology results if available
- ✓Imaging confirming pleural effusion with features suggesting malignancy (nodular pleural thickening, associated mass)
- ✓Treatment plan including drainage, pleurodesis, or indwelling pleural catheter placement
Commonly Confused Codes
- •J91.8: Pleural effusion in other conditions classified elsewhere is used for non-malignant effusions secondary to other diseases
- •J90: Pleural effusion not elsewhere classified is for effusions without identified cause
- •J86.9: Pyothorax without fistula is infected pleural fluid, which may co-occur with malignant effusion
- •C78.2: Secondary malignant neoplasm of pleura codes the metastatic disease directly and may be coded alongside J91.0