ICD-10 Code I28.9 – Disease of pulmonary vessels, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I28.9 – Disease of pulmonary vessels, unspecified
What it is
I28.9 identifies a disorder of the pulmonary vessels when the documentation does not name a more specific condition. Use it for a nonspecific pulmonary vascular disease affecting the arteries or veins in the lungs.
Clinical signs
Clinical features vary; refer to documentation. Patients may have findings related to pulmonary vascular disease, but the record should clearly support a lung-vessel disorder rather than a more specific diagnosis.
When to use this code
Use I28.9 when the provider documents disease of the pulmonary vessels without further detail. It fits cases where the type, cause, or exact vessel involved is not specified in the note. If the chart later identifies a more specific pulmonary vascular condition, code that diagnosis instead.
Do not use for
Do not use this code when the documentation supports a specific pulmonary vascular disorder, such as pulmonary embolism or pulmonary hypertension. Check documentation if the condition is described with another exact diagnosis.
Coding tip
Query for specificity whenever possible; I28.9 is a fallback code, not a substitute for a documented exact pulmonary vascular diagnosis.