2025 ICD-10-CM Diagnosis Code D51.9

Vitamin B12 deficiency anemia, unspecified

ICD-10-CM Code:
D51.9
ICD-10 Code for:
Vitamin B12 deficiency anemia, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

D51.9 is a billable diagnosis code used to specify a medical diagnosis of vitamin b12 deficiency anemia, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.

Unspecified diagnosis codes like D51.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Code Classification

  • Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
    D50–D89
    • Nutritional anemias
      D50-D53
      • Vitamin B12 deficiency anemia
        D51

Approximate Synonyms

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

  • Biermer's congenital pernicious anemia
  • Megaloblastic anemia due to vitamin B>12< deficiency
  • Pernicious anemia
  • Pernicious anemia
  • Selective malabsorption of cyanocobalamin
  • Vegan's anemia
  • Vitamin B12 deficiency anemia due to dietary causes
  • Vitamin B12 deficiency anemia due to malabsorption with proteinuria

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Nutritional anemia

CCSR Code: BLD001

Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.

Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Convert D51.9 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

B12 defic anemia NEC

ICD-9-CM: 281.1

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

Patient Education


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.

Anemia has three main causes: blood loss, lack of red blood cell production, and high rates of red blood cell destruction.

Conditions that may lead to anemia include:

  • Heavy periods
  • Pregnancy
  • Ulcers
  • Colon polyps or colon cancer
  • Inherited disorders
  • A diet that does not have enough iron, folic acid or vitamin B12
  • Blood disorders such as sickle cell anemia and thalassemia, or cancer
  • Aplastic anemia, a condition that can be inherited or acquired
  • G6PD deficiency, a metabolic disorder

Anemia can make you feel tired, cold, dizzy, and irritable. You may be short of breath or have a headache.

Your doctor will diagnose anemia with a physical exam and blood tests. Treatment depends on the kind of anemia you have.

NIH: National Heart, Lung, and Blood Institute


[Learn More in MedlinePlus]

B Vitamins

The B vitamins are:

  • B1 (thiamine)
  • B2 (riboflavin)
  • B3 (niacin)
  • B5 (pantothenic acid)
  • B6
  • B7 (biotin)
  • B12
  • Folic acid

These vitamins help the process your body uses to get or make energy from the food you eat. They also help form red blood cells. You can get B vitamins from proteins such as fish, poultry, meat, eggs, and dairy products. Leafy green vegetables, beans, and peas also have B vitamins. Many cereals and some breads have added B vitamins.

Not getting enough of certain B vitamins can cause diseases. A lack of B12 or B6 can cause anemia.


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.