D50.9: Iron deficiency anemia, unspecified

The ICD-10-CM code for iron deficiency anemia when the record does not specify blood loss, malabsorption, inadequate intake or another cause.

Billable

FY2027

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At a glance

Code Family

D50: Iron deficiency anemia.

HCC Mapping (v28)

No HCC mapping. D50.9 does not map to any CMS-HCC v28 category.

Condition

Iron deficiency anemia

Billable

Yes

Effective Date

Valid in the FY2026 code set and unchanged in the FY2027 update.

Family Specificity

Four billable child codes split on the documented cause of the iron deficiency, with D50.9 as the residual code when no cause is recorded.

Which D50 code do I assign?

The D50 family splits on the documented cause of the iron deficiency rather than on its severity. Reserve D50.9 for iron deficiency anemia recorded without a stated cause.

When documentation says…

Code

Iron deficiency anemia from chronic GI blood loss

D50.0

Iron deficiency anemia secondary to blood loss (chronic). The Index sends Anemia, iron deficiency, secondary to blood loss (chronic) here. The note must identify the chronic blood loss.

Plummer-Vinson syndrome

D50.1

Sideropenic dysphagia, the presentation combining iron deficiency anemia with esophageal webs and dysphagia. Also recorded as Kelly-Paterson syndrome.

Other specified iron deficiency anemia

D50.8

An iron deficiency anemia whose type is documented but matches neither D50.0 nor D50.1. The note must state the specified type.

Iron deficiency anemia, cause not stated

D50.9

Iron deficiency anemia with no documented etiology. Use this code when the record confirms the diagnosis but does not attribute it to blood loss, malabsorption or inadequate intake.

Anemia of chronic kidney disease

D63.1

Anemia in chronic kidney disease, a separate condition that requires the associated N18 code. Do not assign D50.9 for the same anemia.

Anemia, type not established

D64.9

Anemia, unspecified, used when the workup has not confirmed iron deficiency. The provider must document iron deficiency before D50.9 is assigned.

Tabular notes

EXCLUDES1

D50.9 carries no Excludes1 restriction in the FY2027 tabular. No condition is barred from being reported alongside it by an Excludes1 note.

CODE FIRST

D50.9 carries no Code First instruction, and neither does category D50 or D50.0. Anemia in chronic kidney disease is coded D63.1, which carries a Code first note for the underlying chronic kidney disease (the N18 codes).

FY2027: EFFECTIVE 1 OCTOBER 2026

The FY2027 codes and tabular addenda make no addition, deletion or revision in category D50. D50.9 is unchanged in the FY2027 update.

Operational & financial impact

Why specificity matters beyond the chart: risk adjustment, DRG assignment and denial exposure all follow from which code is selected.

CMS-HCC v28 (PY2024+)

D50.9 does not map to any Hierarchical Condition Category under CMS-HCC Model Version 28.

CMS-HCC v28 is fully operative at 100 percent weight for Medicare Advantage payment year 2026.

Iron deficiency anemia unspecified is not a risk adjusting condition under the current CMS model.

WHERE SPECIFICITY IS LOST

Certain aplastic anemia and acquired hemolytic anemia categories do carry HCC designations. D50.9 is not among them.

D50.0 identifies chronic blood loss as the cause. D50.9 does not convey the cause.

D63.1 captures anemia in chronic kidney disease and is reported with the associated N18 code. Assigning D50.9 in its place drops the renal link from the record.

COVERAGE CONTEXT

There is no National Coverage Determination specific to D50.9.

The code supports medical necessity for iron supplementation, intravenous iron therapy and related monitoring.

D50.9 generates no HCC risk adjustment weight under CMS-HCC v28.

Documentation checklist to support D50.9

Chart elements that support code selection and reduce specificity-driven denials.

Clinician documentation of iron deficiency anemia as a confirmed diagnosis.

A statement of the etiology, or a clear indication that no cause has been established.

Laboratory correlation showing low hemoglobin or hematocrit, low serum ferritin and elevated total iron binding capacity.

Clinical interpretation of those laboratory findings, because abnormal indices alone do not support the diagnosis.

Confirmation that the anemia is not attributed to chronic blood loss, which would direct the encounter to D50.0.

Confirmation that the anemia is not anemia of chronic kidney disease, which would direct the encounter to D63.1 with the associated N18 code.

Where a medication is the documented cause, the adverse effect detail needed to support the adverse effect code alongside the anemia.

For outpatient encounters, evidence that the clinician addressed the anemia rather than only recording an abnormal CBC value.

FAQ

Is D50.9 a billable code?

Yes. D50.9 is billable at the fourth character level. It may be reported as a principal or a secondary diagnosis.

When should I use D50.0 instead of D50.9?

Use D50.0 when the record documents that the iron deficiency is secondary to chronic blood loss, such as gastrointestinal bleeding or heavy menstrual bleeding. The Index sends Anemia, iron deficiency, secondary to blood loss (chronic) to D50.0. Use D50.9 only when no cause is documented.

Does D50.9 map to an HCC in 2026?

No. D50.9 does not map to any category in CMS-HCC Model Version 28, which is fully operative at 100 percent weight for payment year 2026. Iron deficiency anemia unspecified carries no risk adjustment weight.

What must the chart show to support D50.9?

The clinician must document iron deficiency anemia as a confirmed diagnosis. Laboratory findings such as low hemoglobin, low serum ferritin and elevated total iron binding capacity support that diagnosis. Abnormal values on their own are not sufficient without clinical interpretation.

How is D50.9 sequenced?

Sequence D50.9 as the principal or primary diagnosis when iron deficiency anemia is the reason for the encounter. D50.9 carries no Code first instruction. Anemia documented as due to chronic kidney disease is coded D63.1, which carries a Code first note for the N18 code.

Can D50.9 and D63.1 be reported together?

D50.9 and D63.1 are not reported together for the same anemia. D63.1 covers anemia in chronic kidney disease and requires the associated N18 code. If both codes appear for what looks like a single anemia, query the provider.

Does D50.9 work differently for inpatient and outpatient encounters?

Yes. On the outpatient side, assign D50.9 only when the clinician documents and addresses the anemia as a condition. On the inpatient side, if the admission workup establishes a specific etiology, assign the more specific code at discharge.

Did anything change for D50.9 in FY2027?

D50.9 is unchanged in the FY2027 update. The FY2027 update, effective 1 October 2026, makes no addition, deletion or revision in category D50.

Related codes

Codes in the same family as D50.9. Only codes with a published page render as links.

Sibling codes in the D50 family

D50.0: Iron deficiency anemia secondary to blood loss (chronic).
D50.1: Sideropenic dysphagia (Kelly-Paterson or Plummer-Vinson syndrome).
D50.8: Other iron deficiency anemias.

Additional codes to consider

Codes outside the D50 family considered alongside D50.9.

Companion: code alongside when documented

Z13.0: Encounter for screening for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism.

Consider instead

D63.1: Anemia in chronic kidney disease, reported with the associated N18 code.
D64.9: Anemia, unspecified, where iron deficiency has not been confirmed.
D51.0: Vitamin B12 deficiency anemia due to intrinsic factor deficiency.
D52.9: Folate deficiency anemia, unspecified.
D61.9: Aplastic anemia, unspecified.

Sources

All claims on this page derive from government and professional-standards sources.

National Center for Health Statistics. (2026). International classification of diseases, tenth revision, clinical modification (ICD-10-CM) FY2027 files. https://www.cdc.gov/nchs/icd/icd-10-cm/files.html
Centers for Medicare & Medicaid Services and National Center for Health Statistics. (2026). ICD-10-CM official guidelines for coding and reporting FY2027. https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Publications/ICD10CM/2027/ICD-10-CM-October-1-2026-FY27-Guidelines.pdf
Centers for Medicare & Medicaid Services. (2025). 2026 model software/ICD-10 mappings. https://www.cms.gov/medicare/payment/medicare-advantage-rates-statistics/risk-adjustment/2026-model-software-icd-10-mappings
Centers for Medicare & Medicaid Services. (2026). MS-DRG classifications and software, version 44. https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps/ms-drg-classifications-and-software