2027 ICD-10-CM Diagnosis Code D51.1Vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria

ICD-10-CM Codes›D50–D89›D50-D53›D51

ICD-10-CM D51.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

D51.1 is a billable ICD-10-CM diagnosis code for vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 811 through 812. Coders also document this condition as familial megaloblastic anemia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nutritional anemia.

Code Identity

ICD-10-CM Code
D51.1
Billable Status
Yes — Valid for Submission
Code Describes
Vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria
Short Description
Vit B12 defic anemia d/t slctv vit B12 malabsorp w protein
Parent Code
D51
Vitamin B12 deficiency anemia

Code Classification

ChapterD50–D89Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
SectionD50-D53Nutritional anemias
CategoryD51Vitamin B12 deficiency anemia
This CodeD51.1Vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Familial megaloblastic anemia
  • Megaloblastic anemia due to inborn errors of metabolism
  • Megaloblastic anemia due to vitamin B>12< malabsorption with proteinuria
  • Pernicious anemia
  • Selective malabsorption of cyanocobalamin
  • Vitamin B12 deficiency anemia due to malabsorption with proteinuria

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to D51.1: its own notes plus those printed at D51 and Chapter 3. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Imerslund (Gräsbeck) syndrome
  • Megaloblastic hereditary anemia

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From D51 Vitamin B12 deficiency anemia applies to 6 codes
  • deficiency of other B group vitamins (E53-)
From Chapter 3 (D50-D89) Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism applies to 324 codes
  • autoimmune disease (systemic) NOS (M35.9)
  • certain conditions originating in the perinatal period (P00-P96)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • human immunodeficiency virus [HIV] disease (B20)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name D51.1, its category, or a range that includes it.

Excludes2 3

These codes carry an Excludes2 note naming D51.1: its condition is not part of those codes, and both may be reported when the patient has both.

  • E53.8 Deficiency of other specified B group vitamins
    vitamin B12 deficiency anemia (D51.-) names D51.-, which includes this code
  • Block E40-E46 Malnutrition
    nutritional anemias (D50-D53) names D50-D53, which includes this code
  • Block E50-E64 Other nutritional deficiencies
    nutritional anemias (D50-D53) names D50-D53, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR BLD001
Nutritional anemia
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Anemia

If you have anemia, your blood does not carry enough oxygen to the rest of your body. The most common cause of anemia is not having enough iron. Your body needs iron to make hemoglobin. Hemoglobin is an iron-rich protein that gives the red color to blood. It carries oxygen from the lungs to the rest of the body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert D51.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
281.1 B12 defic anemia NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About D51.1Overview

Is D51.1 (Vitamin B12 deficiency anemia) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does D51.1 group to?

When vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria is the principal diagnosis on an inpatient stay, it groups to MS-DRG 812, 811, with relative weights from 0.9237 to 1.3991 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of D51.1?

Under the General Equivalence Mappings, vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria converts to ICD-9-CM 281.1 (B12 defic anemia NEC). The mapping is approximate, so confirm the match fits the documentation.