Excludes1 pair

B51.0 vs D77

B51.0 and D77 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on D77
rupture of spleen due to Plasmodium vivax malaria (B51.0)
B51.0

Plasmodium vivax malaria with rupture of spleen

Billable
Chapter 1
Certain infectious and parasitic diseases
Section
B50-B64
Indexed under
  • Rupture, ruptured › spleen › due to P. vivax malaria
  • Malaria, malarial › vivax › with › ruptured spleen
D77

Other disorders of blood and blood-forming organs in diseases classified elsewhere

Billable
Chapter 3
Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
Section
D70-D77
Indexed under
  • Purpura › scorbutic
  • Splenitis › malarial
  • Splenomegaly, splenomegalia › malarial
  • Cyst › spleen NEC › hydatid
  • Degeneration, degenerative › spleen › amyloid

These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027