Excludes1 pair
D56.3 vs D57.3
D56.3 and D57.3 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 D56.3
sickle-cell trait (D57.3)
D56.3
Thalassemia minor
Billable
- Chapter 3
- Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Section
- D55-D59
Use when the record says
- Alpha thalassemia minor
- Alpha thalassemia silent carrier
- Alpha thalassemia trait
- Beta thalassemia minor
- Beta thalassemia trait
- Delta-beta thalassemia minor
- Delta-beta thalassemia trait
- Thalassemia trait NOS
Indexed under
- Thalassemia › minor
- Thalassemia › trait
- Trait › Lepore
- Thalassemia › alpha › minor
- Thalassemia › alpha › silent carrier
D57.3
Sickle-cell trait
Billable
- Chapter 3
- Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Section
- D55-D59
Use when the record says
- Hb-S trait
- Heterozygous hemoglobin S
Indexed under
- Hemoglobin › AS genotype
- Hemoglobin › S, heterozygous (Hb S)
- Sickle-cell › trait
- Sicklemia › trait
- Trait › Hb-S
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