E16.2 vs R79
E16.2 and R79 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 R79
hypoglycemia NOS (E16.2)
E16.2
Hypoglycemia, unspecified
BillableUnspecified
- Chapter 4
- Endocrine, nutritional and metabolic diseases
- Section
- E15-E16
Indexed under
- Glycopenia
- Hypoglycemia (spontaneous)
- McQuarrie's syndrome (idiopathic familial hypoglycemia)
- Decrease › glucose (d)
- Encephalopathy › hypoglycemic (acute)
R79
Other abnormal findings of blood chemistry
Not billable
- Chapter 18
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
- Section
- R70-R79
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