ICD-10 Code J91 – Pleural effusion in conditions classified elsewhere (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J91 – Pleural effusion in conditions classified elsewhere
What it is
J91 identifies a pleural effusion that occurs because of another underlying condition. Use it when the fluid in the pleural space is documented as secondary to a separate disease process.
Clinical signs
Common findings include shortness of breath, chest discomfort, reduced breath sounds, and dullness to percussion. Clinical features vary; refer to documentation and imaging or procedural reports supporting pleural fluid.
When to use this code
Use J91 when the record states the pleural effusion is due to, or associated with, another classified condition rather than a primary pleural disorder. This applies when the underlying cause is documented and the effusion is part of that condition. Code the underlying disease first when instructed by the record and official guidance.
Do not use for
Do not use J91 for an unspecified pleural effusion without a documented cause. Do not use it when the effusion is the primary pleural diagnosis or when documentation does not support a secondary relationship.
Coding tip
Confirm the underlying condition in the chart before assigning J91, and link the effusion to that cause in your coding logic.