According to the ICD-10-CM Official Guidelines for Coding and Reporting, if the type of diabetes mellitus is not documented in the medical record, the default type is E11.-, Type 2 diabetes mellitus. The diagnosis "diabetic polyneuropathy" implies a causal relationship between diabetes and the neurological complication. ICD-10-CM provides a specific combination code that captures both the underlying condition and the manifestation. The Alphabetic Index entry for "Polyneuropathy, diabetic" directs the coder to E11.42. This single code fully describes the diagnosis of Type 2 diabetes mellitus with diabetic polyneuropathy.

A. E10.42: This code is for Type 1 diabetes. The guidelines require defaulting to Type 2 when the type is not specified.

B. E11.9, G62.9: This is incorrect because a specific combination code (E11.42) exists. E11.9 indicates diabetes without complications, which contradicts the diagnosis.

C. E10.9, G62.9: This is incorrect as it assumes Type 1 diabetes and fails to use the appropriate, more specific combination code.

1. ICD-10-CM Official Guidelines for Coding and Reporting FY 2024. National Center for Health Statistics.

Section I.C.4.a.1. Type of diabetes: "If the type of diabetes mellitus is not documented in the medical record

the default is E11.-

Type 2 diabetes mellitus."

Section I.C.4.a.3. Complications due to diabetes mellitus: This section details the use of combination codes for diabetic complications

noting that the codes under categories E08-E13 include the type of diabetes and the complication.

2. ICD-10-CM Codebook (2024). American Medical Association (AMA) or other official publisher.

Alphabetic Index: Under the main term "Polyneuropathy

" the subterm "diabetic" directs to "see Diabetes

with

polyneuropathy." Following this path leads to code E11.42 for the unspecified type.

Tabular List: Code E11.42 is explicitly defined as "Type 2 diabetes mellitus with diabetic polyneuropathy."