ICD-10-CM 2027 diagnosis code

E51Thiamine deficiency

Not billable — use a more specific code

E51 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About E51

E51 is the ICD-10-CM diagnosis code for thiamine deficiency. It belongs to block E50-E64 (other nutritional deficiencies) and chapter 4 (endocrine, nutritional and metabolic diseases). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: E51.1 (beriberi), E51.2 (encephalopathy), E51.8 (deficiency) and E51.9 (unspecified).

Don't report E51 together with the conditions in its Excludes1 note: sequelae of thiamine deficiency (E64.8).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under E51

Coding notes

Excludes1Not coded here — never report together with this code

sequelae of thiamine deficiency (E64.8)

Notes that apply from higher levels

Instructions written at a parent level also apply to E51.

Broader instructions also apply from E50-E64 Other nutritional deficiencies and Chapter 4: Endocrine, nutritional and metabolic diseases.

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about E51

Is E51 billable?: No. E51 is a header code. Report one of its more specific subcodes instead.