D58.2 vs D74.0
D58.2 and D74.0 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on D58.2
Hb-M disease (D74.0)
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
- Anemia › Heinz body, congenital (essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
- Hemoglobin › Constant Spring
D74.0
Congenital methemoglobinemia
Billable
- Chapter 3
- Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Section
- D70-D77
Use when the record says
- Congenital NADH-methemoglobin reductase deficiency
- Hemoglobin-M [Hb-M] disease
- Methemoglobinemia, hereditary
Indexed under
- Deficiency, deficient › NADH diaphorase or reductase
- Deficiency, deficient › NADH-methemoglobin reductase
- Disease, diseased › diaphorase deficiency
- Methemoglobinemia › congenital
- Methemoglobinemia › enzymatic
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