Other primary thrombocytopenia

This code represents a primary (idiopathic) reduction in platelet count not otherwise specified, indicating a disorder where the body's immune system mistakenly attacks and destroys its own platelets. It signifies a diagnosis of thrombocytopenia without an identifiable secondary cause such as medication, infection, or other underlying systemic diseases.

Use this code when documentation clearly states "primary thrombocytopenia NOS," "idiopathic thrombocytopenia NOS," or similar phrasing where the specific type of primary thrombocytopenia (e.g., immune thrombocytopenia) is not further elaborated. It is appropriate when the etiology of the low platelet count is determined to be primary but lacks further diagnostic specificity.

• Avoid using this code if a more specific type of primary thrombocytopenia, such as immune thrombocytopenia (ITP), is documented.
• Ensure documentation rules out secondary causes of thrombocytopenia before assigning this code.
• Consider sequencing this code as a principal diagnosis when it is the primary reason for the encounter.