Anemia may seem uncomplicated on a laboratory report, but it’s rarely so simple to identify an anemia diagnosis when you notice a low hemoglobin.
For physicians, hospitals and clinics accurate anemia coding relies on an important question: what form of anemia does the patient actually have and what is causing it?
A low hemoglobin level can be caused by different kinds of anemia. Iron‑deficiency anemia, anemia caused by blood loss, anemia that comes from kidney disease anemia caused by chemotherapy, anemia due, to a lack of vitamin B12 and hemolytic anemia are all examples. However each kind of anemia can look different. May not be found or named in the same way.
The provider documentation drives the right ICD-10 code for anemia as well as the underlying ailment, etiology, acuity and clinical conditions.
This guide, for 2026 includes the common anemia ICD-10-CM codes. It covers documentation requirements, related diagnosis codes laboratory CPT codes, treatment options, sequencing rules and frequent claim problems. Physicians and healthcare organizations should pay attention to these points.
What Is the ICD-10 Code for Anemia?
There is no single ICD-10-CM code that represents every form of anemia.
One of the most commonly reported codes is:
D64.9 — Anemia, unspecified
However D64.9 should generally be used when the medical record supports a diagnosis of anemia but does not identify a specific type or cause.
When physicians have determined the type of anemia a more specific code is usually appropriate.
Common anemia categories include:
| Condition | Common ICD-10-CM Code |
|---|---|
| Anemia, unspecified | D64.9 |
| Iron deficiency anemia, unspecified | D50.9 |
| Iron deficiency anemia due to chronic blood loss | D50.0 |
| Acute posthemorrhagic anemia | D62 |
| Vitamin B12 deficiency anemia, unspecified | D51.9 |
| Folate deficiency anemia, unspecified | D52.9 |
| Anemia in neoplastic disease | D63.0 |
| Anemia in chronic kidney disease | D63.1 |
| Anemia in other chronic diseases | D63.8 |
| Anemia due to antineoplastic chemotherapy | D64.81 |
| Other specified anemia | D64.89 |
CMS’s FY 2026 coding resources continue to identify D63.0, D63.1, D63.8, D64.81, D64.89, and D64.9 as distinct diagnoses, emphasizing why clinicians should document the actual clinical type whenever known.
Understanding Anemia Before Choosing an ICD-10 Code
Anemia happens when the blood cannot carry oxygen properly. This condition is usually noticed when hemoglobin levels are low or when hematocrit levels are low. Anemia is not one disease. It is a syndrome that can have different causes.
Symptoms of Anemia may be fatigue, weakness, shortness of breath, dizziness, heart rhythm less ability to exercise, palpitations or paleness. Some people may not feel symptoms especially if Anemia grows slowly.
From a coding standpoint, the laboratory aberration alone may not necessarily provide the full diagnosis.
Low hemoglobin may need tests, such as iron studies, vitamin B12 tests, folate level checks, kidney function tests, reticulocyte counts, peripheral smear exams, hemolysis studies, endoscopy, bone marrow exams or other tests.
After the low hemoglobin diagnosis is made the record must note the type of test and the reason, for it whenever possible.
D64.9: Anemia, Unspecified
ICD-10-CM D64.9 represents:
Anemia, unspecified
This is often the code people are referring to when searching for a general ICD-10 code for anemia.
D64.9 may be acceptable when anemia is detected clinically. However documentation does not confirm whether anemia is related to iron deficiency, blood loss, kidney illness, inadequate diet, chemotherapy, hemolysis or another recognized cause.
Example
A patient presents with fatigue. Laboratory testing demonstrates reduced hemoglobin and hematocrit. The physician documents:
Anemia—etiology currently unclear. Iron studies and B12 testing ordered.
At that stage, D64.9 may reasonably reflect the documented diagnosis.
If the next test shows that someone has iron deficiency anemia the correct code, from category D50 should be used. Do not keep using the code for anemia forever.
Why Overuse of D64.9 Can Cause Problems
Unspecified coding can reduce the clinical detail carried on a claim.
When the medical record clearly shows iron deficiency anemia caused by kidney disease, anemia from blood loss or anemia caused by chemotherapy using D64.9 instead of the correct specific diagnosis can create problems between the claim and the medical record.
Detailed documentation is especially important when treatment such, as iron infusion drugs that stimulate blood cell production, blood transfusion or a specialists evaluation is needed to prove that the treatment is necessary.
Iron Deficiency Anemia ICD-10 Codes
Iron deficiency is one of the most frequently encountered causes of anemia.
ICD-10-CM places iron deficiency anemia primarily within category D50.
Important codes include:
| ICD-10 Code | Description |
|---|---|
| D50.0 | Iron deficiency anemia secondary to blood loss (chronic) |
| D50.1 | Sideropenic dysphagia |
| D50.8 | Other iron deficiency anemias |
| D50.9 | Iron deficiency anemia, unspecified |
These codes remain represented in CMS FY 2026 coding materials.
D50.9 — Iron Deficiency Anemia, Unspecified
D50.9 is appropriate when the provider has diagnosed iron deficiency anemia but has not documented a more specific cause that corresponds with another available code.
Clinical documentation may include findings such as:
- Low hemoglobin
- Low serum iron
- Reduced ferritin
- Reduced transferrin saturation
- Elevated total iron-binding capacity in appropriate clinical situations
- Microcytosis
- Hypochromia
These laboratory findings may support the diagnosis. I see that the physician’s documented clinical assessment remains central to code selection.
D50.0: Iron Deficiency Anemia Due to Chronic Blood Loss
D50.0 represents iron deficiency anemia secondary to chronic blood loss.
This diagnosis can happen in people who have conditions like long-term bleeding, in the stomach or intestines heavy periods, repeated areas that bleed or any other ongoing cause of losing blood.
Documentation should ideally identify both:
- The iron deficiency anemia.
- The underlying cause of chronic blood loss when known.
For example, documenting simply “anemia” provides substantially less coding information than:
Iron deficiency anemia secondary to chronic gastrointestinal blood loss.
Depending on the case, the underlying gastrointestinal, gynecologic, or other condition may require separate coding.
D62: Acute Posthemorrhagic Anemia
D62 — Acute posthemorrhagic anemia is used when anemia results from acute blood loss.
CMS continues to identify D62 separately from chronic blood-loss and unspecified anemia diagnoses.
This distinction is clinically important.
For example:
Chronic gastrointestinal blood loss resulting in iron deficiency
may support:
D50.0
while:
Acute blood loss following significant hemorrhage
may support:
D62
Providers should document the acuity and relationship between the bleeding event and anemia rather than relying solely on declining hemoglobin values.
A postoperative drop, in hemoglobin for example does not automatically mean blood-loss anemia. I think the provider still needs to diagnose acute blood-loss anemia.
Vitamin B12 Deficiency Anemia ICD-10 Codes
Vitamin B12 deficiency anemia falls primarily within category D51.
Common codes include:
| ICD-10 Code | Condition |
|---|---|
| D51.0 | Vitamin B12 deficiency anemia due to intrinsic factor deficiency |
| D51.1 | Vitamin B12 deficiency anemia due to selective vitamin B12 malabsorption with proteinuria |
| D51.2 | Transcobalamin II deficiency |
| D51.3 | Other dietary vitamin B12 deficiency anemia |
| D51.8 | Other vitamin B12 deficiency anemias |
| D51.9 | Vitamin B12 deficiency anemia, unspecified |
CMS’s 2026 materials list these diagnoses separately, allowing substantially greater specificity than D64.9 when the cause has been established.
Physicians should document whether the deficiency is dietary, related to intrinsic factor deficiency, associated with malabsorption, or otherwise specified when the information is clinically available.
Folate Deficiency Anemia ICD-10 Codes
Folate deficiency anemia falls under category D52.
Common codes include:
| ICD-10 Code | Description |
|---|---|
| D52.0 | Dietary folate deficiency anemia |
| D52.1 | Drug-induced folate deficiency anemia |
| D52.8 | Other folate deficiency anemias |
| D52.9 | Folate deficiency anemia, unspecified |
CMS FY 2026 documentation continues to recognize these separate codes.
When medication causes anemia it’s important to document the connection whenever it makes sense. This is because drug-related conditions may require coding steps.
Anemia in Chronic Kidney Disease: D63.1
D63.1 — Anemia in chronic kidney disease
is an important code for nephrology practices, hospitals, primary care physicians, and clinics managing patients with chronic renal disease.
Anemia in CKD frequently develops as kidney function declines, in part because impaired kidneys may produce insufficient erythropoietin.
However, D63.1 should not generally stand alone without documentation of the patient’s underlying CKD.
Examples of related CKD codes include:
| ICD-10-CM Code | CKD Stage |
|---|---|
| N18.1 | CKD stage 1 |
| N18.2 | CKD stage 2 |
| N18.30 | CKD stage 3, unspecified |
| N18.31 | CKD stage 3a |
| N18.32 | CKD stage 3b |
| N18.4 | CKD stage 4 |
| N18.5 | CKD stage 5 |
| N18.6 | End-stage renal disease |
For certain Medicare erythropoiesis-stimulating agent claims, CMS expects documentation and diagnosis coding identifying both anemia of CKD and the relevant renal condition. For example, CMS coverage guidance for patients with ESRD identifies D63.1 together with N18.6.
Example
A nephrologist documents:
Anemia secondary to stage 4 chronic kidney disease.
Relevant coding may include:
N18.4 — Chronic kidney disease, stage 4
and
D63.1 — Anemia in chronic kidney disease
The exact sequencing and additional codes should follow the circumstances of the encounter and current ICD-10-CM instructions.
D63.0: Anemia in Neoplastic Disease
D63.0 — Anemia in neoplastic disease
is used when anemia is associated with an underlying malignancy rather than being caused by chemotherapy.
This distinction is particularly important in oncology.
When an encounter is specifically for management of anemia associated with a malignancy and treatment is directed only at that anemia, ICD-10-CM guidelines specify that the malignancy is sequenced first, followed by the anemia diagnosis.
For example, documentation might indicate:
Anemia due to metastatic lung cancer.
The appropriate malignancy code would therefore need to be considered in addition to D63.0.
D64.81: Anemia Due to Antineoplastic Chemotherapy
Anemia caused by chemotherapy is different from anemia caused by the malignancy itself.
D64.81 — Anemia due to antineoplastic chemotherapy
may be appropriate when the medical record clearly establishes chemotherapy as the cause.
CMS identifies D64.81 as a distinct diagnosis in FY 2026 materials.
Depending on the circumstances, additional coding may be necessary for the malignancy and the adverse effect of the antineoplastic medication.
This distinction matters because:
Anemia caused by cancer
and
anemia caused by chemotherapy used to treat cancer
are not interchangeable diagnoses.
Medicare ESA policies may also require specific diagnosis combinations and modifiers. One current CMS coverage article, for example, identifies D64.81 together with a qualifying non-myeloid malignancy diagnosis for certain ESA claims and requires applicable modifiers such as EA as well as the route-of-administration modifier JA or JB.
Providers should always verify the applicable payer’s policy rather than assuming the same requirements apply to every plan.
Anemia in Other Chronic Diseases: D63.8
D63.8 — Anemia in other chronic diseases classified elsewhere
may be considered when anemia is caused by another qualifying chronic condition and a more specific anemia category does not apply.
Because this is an underlying-disease relationship code, clinical documentation should clearly connect the anemia to the chronic disease.
Do not assume causation solely because anemia and another chronic disease appear in the same chart.
A statement such as:
Anemia associated with chronic inflammatory disease
provides substantially stronger coding support than listing the two diagnoses independently without establishing their relationship.
Hemolytic Anemia ICD-10 Codes
Hemolytic anemia results from accelerated destruction of red blood cells and includes several distinct disorders.
ICD-10-CM provides numerous specific diagnoses rather than a single generic hemolytic anemia code.
Examples include:
| ICD-10 Code | Description |
|---|---|
| D59.0 | Drug-induced autoimmune hemolytic anemia |
| D59.10 | Autoimmune hemolytic anemia, unspecified |
| D59.11 | Warm autoimmune hemolytic anemia |
| D59.12 | Cold autoimmune hemolytic anemia |
| D59.13 | Mixed type autoimmune hemolytic anemia |
| D59.19 | Other autoimmune hemolytic anemia |
| D59.2 | Drug-induced nonautoimmune hemolytic anemia |
| D59.5 | Paroxysmal nocturnal hemoglobinuria |
| D59.9 | Acquired hemolytic anemia, unspecified |
CMS FY 2026 materials specifically identify warm, cold, mixed, drug-induced, and other autoimmune hemolytic anemia categories.
That degree of specificity makes clear provider documentation particularly valuable.
Writing “hemolytic anemia” may not communicate whether the disease is autoimmune, drug-induced, inherited, acquired, warm-antibody mediated, or cold-antibody mediated.
Aplastic Anemia and Bone Marrow Failure Codes
Aplastic anemia and related bone marrow failure syndromes generally fall within category D61.
Examples include:
| ICD-10 Code | Description |
|---|---|
| D61.01 | Constitutional pure red blood cell aplasia |
| D61.03 | Fanconi anemia |
| D61.1 | Drug-induced aplastic anemia |
| D61.2 | Aplastic anemia due to other external agents |
| D61.3 | Idiopathic aplastic anemia |
| D61.810 | Antineoplastic chemotherapy induced pancytopenia |
| D61.811 | Other drug-induced pancytopenia |
| D61.818 | Other pancytopenia |
| D61.9 | Aplastic anemia, unspecified |
CMS’s FY 2026 definitions distinguish these diagnoses individually.
Clinicians should avoid treating “pancytopenia,” “aplastic anemia,” and ordinary anemia as interchangeable terms. Each describes a different hematologic picture and can lead to different code selection.
Sideroblastic Anemia Codes
Another important group appears within category D64.
Examples include:
D64.0 — Hereditary sideroblastic anemia
D64.1 — Secondary sideroblastic anemia due to disease
D64.2 — Secondary sideroblastic anemia due to drugs and toxins
D64.3 — Other sideroblastic anemias
CMS continues to distinguish these conditions in the 2026 code set.
If a medication, toxin, genetic condition, or underlying disease is responsible, clearly documenting that relationship improves coding specificity.
Common CPT Codes Used During Anemia Evaluation
The diagnosis code explains why a service was medically necessary, while CPT or HCPCS codes describe what service was performed.
Providers evaluating anemia may order several laboratory studies depending on the patient’s presentation.
Common examples include:
| CPT Code | Common Service |
|---|---|
| 85025 | Complete blood count with automated differential |
| 85027 | Complete blood count without automated differential |
| 85045 | Reticulocyte count |
| 83540 | Iron |
| 83550 | Iron-binding capacity |
| 82728 | Ferritin |
| 82607 | Vitamin B12 |
| 82746 | Folate |
| 83615 | Lactate dehydrogenase |
| 83010 | Haptoglobin |
| 82247 | Total bilirubin |
| 36415 | Collection of venous blood by venipuncture |
These tests should not be ordered or billed simply because a patient has an anemia code. Medical necessity should be supported by the patient’s clinical condition, diagnosis, symptoms, and applicable payer requirements.
CPT codes and payer coverage policies can change, so code selection should be verified against the current CPT manual, payer guidance, and applicable Medicare coverage rules before claim submission.
Coding Blood Transfusions and Anemia Treatment
Severe or symptomatic anemia may require treatment ranging from oral supplementation to intravenous iron, vitamin replacement, transfusion, ESA therapy, or treatment of the underlying disease.
Coding therefore depends heavily on the actual service performed.
For example, ESA claims may involve HCPCS codes such as those used for epoetin or darbepoetin products, but Medicare requirements can vary significantly according to whether anemia is associated with CKD, dialysis, chemotherapy, or another condition.
Current CMS coverage documentation demonstrates that some ESA claims require combinations of diagnosis codes rather than an anemia diagnosis alone.
Physicians and hospitals should therefore avoid treating medication coding, diagnosis coding, and medical-necessity documentation as separate processes.
They must support one another.
Documentation Requirements for Accurate Anemia Coding
The quality of anemia coding often begins with the quality of physician documentation.
A strong clinical note should identify the type of anemia whenever that information is known.
Useful elements may include:
Type of anemia
Document whether the condition is:
- Iron deficiency
- Blood-loss related
- Vitamin B12 deficiency
- Folate deficiency
- Hemolytic
- Aplastic
- CKD-associated
- Neoplasm-associated
- Chemotherapy-induced
- Another specified form
Cause
When clinically established, document what is causing the anemia.
Instead of:
“Patient has anemia and CKD.”
consider documenting:
Anemia secondary to stage 4 chronic kidney disease.
when that relationship has actually been established clinically.
Acute versus chronic
Blood-loss anemia particularly requires careful distinction.
“Acute posthemorrhagic anemia” and “iron deficiency anemia secondary to chronic blood loss” represent different clinical situations and different ICD-10-CM codes.
Underlying disease
When anemia results from cancer, CKD, chronic disease, medication, or another condition, the underlying disease should be clearly documented.
Treatment relationship
If chemotherapy or another medication caused the anemia, document that relationship rather than merely listing anemia and medication exposure separately.
Common Anemia Coding Errors That Can Lead to Denials
1. Automatically Using D64.9
D64.9 is not the default code whenever hemoglobin is below the reference range.
If the physician has documented a specific anemia diagnosis, the corresponding specific code should be evaluated.
2. Coding From Laboratory Results Alone
Low hemoglobin, low ferritin, macrocytosis, or another laboratory abnormality may support clinical decision-making, but code assignment should reflect the documented diagnosis.
For example, a ferritin result alone should not automatically be converted into a diagnosis of iron deficiency anemia without appropriate provider documentation.
3. Failing to Code the Underlying Disease
Anemia related to CKD or malignancy frequently requires the underlying disease to be represented appropriately.
This becomes especially important for treatment claims in which the payer expects multiple diagnoses to establish medical necessity.
4. Confusing Cancer-Related Anemia With Chemotherapy-Induced Anemia
These diagnoses are different.
D63.0 generally describes anemia associated with neoplastic disease.
D64.81 describes anemia due to antineoplastic chemotherapy.
The provider’s documentation should establish which relationship is responsible.
5. Confusing Acute and Chronic Blood-Loss Anemia
Acute hemorrhage and chronic blood loss should not automatically receive the same anemia code.
The clinical record should state whether the condition is acute, chronic, or otherwise specified.
6. Using Outdated Codes
This becomes particularly important around the annual ICD-10 transition.
The FY 2026 ICD-10-CM code set applies through September 30, 2026. Beginning October 1, 2026, encounters should be coded using the FY 2027 ICD-10-CM files published by CMS and CDC.
Practices should therefore confirm code-set dates when working claims that cross the September/October transition.
Anemia Claim Denials: What Providers Should Review
An anemia diagnosis does not automatically establish medical necessity for every associated laboratory test, medication, infusion, or procedure.
Common denial causes can include:
Diagnosis does not support medical necessity
The diagnosis submitted may not meet the payer’s coverage criteria for the service.
Missing underlying diagnosis
The claim reports D63.1 for anemia in CKD but fails to appropriately represent the renal disease required by the applicable policy.
Incorrect treatment-related diagnosis
A chemotherapy-induced anemia claim is submitted as unspecified anemia.
Documentation does not match the claim
The medical record describes iron deficiency anemia while the claim reports D64.9.
Insufficient drug documentation
ESA claims may lack the underlying condition, qualifying anemia diagnosis, route-of-administration modifier, or other payer-required information.
Outdated diagnosis code
A claim is submitted using a code that is no longer valid for the date of service.
When these issues are recurring across an organization, working with an experienced revenue cycle partner such as Vermont Medical Billing can help practices identify documentation-to-claim gaps and establish more consistent coding workflows.
How to Improve Anemia Coding Accuracy in a Clinical Practice
Anemia coding becomes considerably easier when documentation and claim preparation follow the same clinical logic.
First, determine whether anemia has actually been diagnosed.
Next, identify whether the physician knows the specific type.
Then determine whether an underlying condition is responsible.
Finally, make sure treatment claims are supported by the diagnosis combination, documentation, laboratory findings, and payer policy required for that service.
For hospitals and multi-specialty clinics, regular review is especially valuable because anemia may be managed across primary care, gastroenterology, oncology, nephrology, hematology, gynecology, surgery, and inpatient services.
Organizations using Vermont Medical Billing for revenue cycle support can also incorporate anemia-related documentation and claim reviews into broader efforts to reduce avoidable coding errors and payer rejections.
Common ICD-10 Codes for Anemia
| ICD-10-CM | Diagnosis |
|---|---|
| D50.0 | Iron deficiency anemia secondary to chronic blood loss |
| D50.9 | Iron deficiency anemia, unspecified |
| D51.0 | Vitamin B12 deficiency anemia due to intrinsic factor deficiency |
| D51.9 | Vitamin B12 deficiency anemia, unspecified |
| D52.0 | Dietary folate deficiency anemia |
| D52.9 | Folate deficiency anemia, unspecified |
| D59.10 | Autoimmune hemolytic anemia, unspecified |
| D59.11 | Warm autoimmune hemolytic anemia |
| D59.12 | Cold autoimmune hemolytic anemia |
| D61.3 | Idiopathic aplastic anemia |
| D61.9 | Aplastic anemia, unspecified |
| D62 | Acute posthemorrhagic anemia |
| D63.0 | Anemia in neoplastic disease |
| D63.1 | Anemia in chronic kidney disease |
| D63.8 | Anemia in other chronic diseases classified elsewhere |
| D64.0 | Hereditary sideroblastic anemia |
| D64.81 | Anemia due to antineoplastic chemotherapy |
| D64.89 | Other specified anemias |
| D64.9 | Anemia, unspecified |
Final Thoughts
Selecting the correct ICD-10 code for anemia requires more than identifying a reduced hemoglobin level.
The most accurate coding reflects the clinical story.
Is the patient iron deficient? Is there chronic gastrointestinal blood loss? Did an acute hemorrhage occur? Is chronic kidney disease responsible? Is the anemia associated with malignancy or caused by chemotherapy? Is there vitamin deficiency, hemolysis, bone marrow failure, or another underlying condition?
Answering those questions allows physicians, hospitals, and clinics to move beyond unspecified coding and produce a claim that more accurately reflects the patient’s diagnosis.
For 2026, practices should also pay close attention to the annual code transition: FY 2026 ICD-10-CM codes remain applicable through September 30, 2026, while the FY 2027 code set becomes effective October 1, 2026.
Accurate diagnosis documentation, appropriate code specificity, correct sequencing, and verification of payer-specific medical-necessity requirements remain the strongest foundation for cleaner anemia claims and fewer preventable coding problems.
Frequently Asked Questions About the ICD-10 Code for Anemia
What is the ICD-10 code for unspecified anemia?
The ICD-10-CM code for unspecified anemia is D64.9.
It is generally appropriate when anemia has been diagnosed but the available documentation does not establish a more specific type.
What is the ICD-10 code for iron deficiency anemia?
D50.9 represents iron deficiency anemia, unspecified.
When iron deficiency anemia results from chronic blood loss, D50.0 may be appropriate.
What is the ICD-10 code for acute blood-loss anemia?
D62 represents acute posthemorrhagic anemia.
The medical record should clinically establish acute blood-loss anemia rather than relying solely on a postoperative or posthemorrhagic reduction in hemoglobin.
What is the ICD-10 code for anemia in chronic kidney disease?
D63.1 represents anemia in chronic kidney disease.
The underlying CKD should also be appropriately documented and coded. Medicare coverage policies for certain anemia treatments may specifically require both anemia and CKD diagnoses.
What is the ICD-10 code for anemia due to chemotherapy?
D64.81 represents anemia due to antineoplastic chemotherapy.
Additional malignancy and adverse-effect coding may be required depending on the circumstances and official guidelines.
Is anemia always coded as D64.9?
No.
D64.9 represents unspecified anemia. If the medical record identifies iron deficiency anemia, CKD-related anemia, acute blood-loss anemia, chemotherapy-induced anemia, or another specific form, a more specific ICD-10-CM code should be evaluated.
Can anemia be coded based only on low hemoglobin?
A laboratory value alone does not necessarily establish the complete clinical diagnosis or cause of anemia.
Physicians should document their clinical assessment, and diagnosis coding should reflect the condition established in the medical record.
