Surgical removal of the spleen, an organ that filters blood and helps fight infection.
Because the 20% rating applies to any confirmed splenectomy, the key evidence is documentation that the spleen was removed. Operative reports, surgical records, discharge summaries, or imaging reports confirming the absence of the spleen all serve that purpose. Pathology reports from the surgery can also confirm removal. If you are claiming separate ratings for complications such as systemic infections with encapsulated bacteria, medical records documenting those infections — including lab results, hospitalization records, and treating-physician notes — would support each separate claim. Statements from you or others describing how complications affect your daily life or work can also help establish the impact of those separately rated conditions.
Conditions that are often caused or made worse by this one. If you have any of these, they may be claimable as secondary service connection.