Excludes1 pair
D56.4 vs D58.2
D56.4 and D58.2 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 D58.2
hereditary persistence of fetal hemoglobin [HPFH] (D56.4)
D56.4
Hereditary persistence of fetal hemoglobin [HPFH]
Billable
- Chapter 3
- Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Section
- D55-D59
Indexed under
- Hemoglobin › fetal, hereditary persistence (HPFH)
- Persistence, persistent › hemoglobin, fetal (hereditary) (HPFH)
- Persistence, persistent › fetal › hemoglobin, hereditary (HPFH)
D58.2
Other hemoglobinopathies
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
- Abnormal hemoglobin NOS
- Congenital Heinz body anemia
- Hb-C disease
- Hb-D disease
- Hb-E disease
- Hemoglobinopathy NOS
- Unstable hemoglobin hemolytic disease
Indexed under
- Heinz body anemia, congenital
- Hemoglobinopathy (mixed)
- Abnormal, abnormality, abnormalities › hemoglobin (disease)
- Anemia › Heinz body, congenital
- Hemoglobin › Constant Spring
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