E51.9

Billable

ChapterE00–E89

Ranksubcategory

Official Description

Thiamine deficiency, unspecified

Metadata & Insights

•2026 ICD-10-CM Edition - Effective October 1, 2025.
•Billable/specific code (valid for reimbursement).
•Chapter 4: Endocrine, Nutritional and Metabolic Diseases (E00-E89).

General instructions are available for the parent sections:

View CH4 Notes View E50-E64 Notes View E51 Notes

Clinical Hierarchy

CH4Endocrine, nutritional and metabolic diseases (E00-E89)

E50-E64Other nutritional deficiencies (E50-E64)

E51Thiamine deficiency

E51.9Thiamine deficiency, unspecified

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to E51.9:

categoryE51

Thiamine deficiency

View context instructions

blockE50-E64

Other nutritional deficiencies (E50-E64)

View context instructions

chapterCH4

Endocrine, nutritional and metabolic diseases (E00-E89)

View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to E51.9. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

6 raw paths

Aneurin deficiency1 unique routes

Direct index entry→E51.9

Deficiency, deficient4 unique routes

aneurin→E51.9

thiamin, thiaminic (chloride)→E51.9

vitamin (multiple) NOS(2 variants)

B1 NOS→E51.9

thiamin→E51.9

Thiamin deficiency1 unique routes

Direct index entry→E51.9

MS-DRG Classification

2026 v43.1

This code is grouped within the following Diagnosis Related Group(s) for clinical reimbursement:

DRG 640

Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes with MCC

DRG 641

Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes without MCC

Cross Reference

Find Procedures (ICD-10-PCS)

Find surgical and procedural codes related to Thiamine deficiency, unspecified.

Search PCS Codes