B20 (Human immunodeficiency virus [HIV] disease) compared with D89.41 (Monoclonal mast cell activation syndrome), from the official CMS tabular data. Both may be reported when both conditions are documented (Excludes2).
Distinct conditions — both may be reported.
“human immunodeficiency virus [HIV] disease (B20)”
An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.
Source: CMS ICD-10-CM tabular instructional notes
Yes, when both are documented. D89.41 carries an Excludes2 note covering B20: “human immunodeficiency virus [HIV] disease (B20)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
| B20Human immunodeficiency virus [HIV] disease | D89.41Monoclonal mast cell activation syndrome | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99) | D50-D89 — Diseases of the Blood and Blood-forming Organs and Certain Disorders Involving the Immune Mechanism (D50-D89) |
| Definition | Human immunodeficiency virus [HIV] disease is a billable ICD-10-CM diagnosis code (B20). | Monoclonal mast cell activation syndrome is a billable ICD-10-CM diagnosis code (D89.41). |
| Includes | acquired immune deficiency syndrome [AIDS] AIDS-related complex [ARC] HIV infection, symptomatic | defects in the complement system immunodeficiency disorders, except human immunodeficiency virus [HIV] disease sarcoidosis |
| Use additional code | code(s) to identify all manifestations of HIV infection | — |
| Code first | Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium, if applicable (O98.7-) | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources