ICD-10 Code D51 – Vitamin B12 deficiency anemia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D51 – Vitamin B12 deficiency anemia
What it is
D51 identifies anemia caused by vitamin B12 deficiency. Use it when the record shows reduced red blood cell production due to lack of cobalamin.
Clinical signs
Common findings include anemia symptoms such as fatigue, weakness, and pallor. Some patients also have neurologic changes, but clinical features vary; refer to documentation.
When to use this code
Use D51 when the provider documents vitamin B12 deficiency anemia, pernicious anemia, or another B12-related megaloblastic anemia. It is appropriate when the anemia is clearly linked to B12 deficiency in the chart.
If the note only states low B12 without anemia, this code may not apply. Check documentation for the exact diagnosis and whether the anemia is confirmed.
Do not use for
Do not use D51 for folate deficiency anemia, iron deficiency anemia, or nonspecific anemia without a documented B12 cause. Check documentation if the chart is unclear.
Coding tip
Assign the code only when the provider links anemia to vitamin B12 deficiency; otherwise, query or code the documented condition.