Combined immunodeficiency, unspecified

This code represents a severe, congenital disorder characterized by a significant impairment in both T-cell and B-cell mediated immunity, leading to recurrent, severe, and often opportunistic infections. The "unspecified" nature indicates that the specific genetic defect or underlying cause of the combined immunodeficiency has not been determined or documented.

Use this code when documentation confirms a diagnosis of combined immunodeficiency, but the specific type or etiology is not identified. This is appropriate for initial diagnoses where further workup is pending or when the specific genetic mutation or syndrome cannot be definitively established.

• Avoid using this code if a more specific type of combined immunodeficiency (e.g., severe combined immunodeficiency [SCID] with specific genetic defect) is documented.
• Always review the medical record for any additional details that might allow for a more precise code selection within the D81 category.
• Consider sequencing this code as a primary diagnosis when it is the main reason for the encounter, especially for diagnostic workup or management of the immunodeficiency.