E10 vs Q45.3
E10 and Q45.3 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 Q45.3
congenital diabetes mellitus (E10.-)
E10
Type 1 diabetes mellitus
Not billable
- Chapter 4
- Endocrine, nutritional and metabolic diseases
- Section
- E08-E13
Use when the record says
- brittle diabetes (mellitus)
- diabetes (mellitus) due to autoimmune process
- diabetes (mellitus) due to immune mediated pancreatic islet beta-cell destruction
- idiopathic diabetes (mellitus)
- juvenile onset diabetes (mellitus)
- ketosis-prone diabetes (mellitus)
Q45.3
Other congenital malformations of pancreas and pancreatic duct
Billable
- Chapter 17
- Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
- Section
- Q38-Q45
Use when the record says
- Accessory pancreas
- Congenital malformation of pancreas or pancreatic duct NOS
Indexed under
- Aberrant › pancreas (congenital)
- Accessory › pancreas (congenital)
- Anomaly, anomalous › pancreas or pancreatic duct (congenital) (unspecified type)
- Deformity › pancreas
- Distortion › pancreas (s) (congenital)
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