D51.9 Vitamin B12 deficiency anemia, unspecified

The ICD-10-CM code for Vitamin B12 deficiency anemia, unspecified is D51.9 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

3: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)

Section

D50-D53: Nutritional anemias (D50-D53)

Category D51

7 codes (6 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to D51.9:

• Anemia (essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound) › deficiency › vitamin B12 NOS
• Degeneration, degenerative › combined (spinal cord) (subacute) › in (due to) › vitamin B12 deficiency › anemia

U.S. Hospital Utilization

• An estimated 23,215 U.S. inpatient stays in 2023 included D51.9 among the documented diagnoses.
• 415 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Chapter 3 TOC entry

3. Chapter 3: Disease of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) ............................................................................................. 39

Reserved for future guideline expansion

Reserved for future guideline expansion ...................................................................................... 39

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)