Immunodeficiency due to external causes

This code signifies a compromised immune system resulting from factors originating outside the body. It describes a state where the body's defense mechanisms are weakened due to an identifiable external cause, rather than an intrinsic genetic defect or autoimmune process.

Use this code when documentation clearly indicates an acquired immunodeficiency directly attributable to an external factor, such as environmental toxins, certain medications (e.g., immunosuppressants for organ transplant, chemotherapy), or radiation exposure. It is appropriate when the cause is explicitly stated as external and leads to a measurable immune deficit.

• Always sequence this code after the primary diagnosis indicating the specific external cause, if applicable.
• Distinguish carefully from D80-D84 codes for primary immunodeficiencies, which are congenital or intrinsic.
• Ensure documentation specifies the external nature of the cause; avoid using for unspecified immunodeficiency.