What is ICD-10 code D61.9?

D61.9 is the ICD-10-CM diagnosis code for Aplastic anemia, unspecified. A serious condition where the bone marrow fails to produce enough blood cells, but the specific cause is not documented or identified. D61.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. D61.9 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. D61.9 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. D61.9 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for D61.9?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. D61.9 was a payment HCC under V24 (Severe Hematological Disorders) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting D61.9?

This is a default code; attempt to determine and code the specific type of aplastic anemia when possible Query the provider if the cause can be identified from clinical documentation Because D61.9 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

D61.9 ICD-10 Code: Aplastic anemia, unspecified

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupD61.9Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) / Aplastic and other anemias and other bone marrow failure syndromes (D60-D64)

D61.9

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Aplastic anemia, unspecified

A serious condition where the bone marrow fails to produce enough blood cells, but the specific cause is not documented or identified.

Buddy Insight

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Mapped

HCC 46

Severe Hematological Disorders

RAF 0.666

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 46

Severe Hematological Disorders

RAF 0.0

RXHCC

Mapped

HCC 96

Hemolytic and Aplastic Anemias

RAF 0.0

Code Trumping

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Code Book Path

Official

D61Other aplastic anemias and other bone marrow failure syndromes

D61.9Aplastic anemia, unspecified

Inclusion Terms

Official

Hypoplastic anemia NOS
Medullary hypoplasia

Excludes 2

Official

neutropenia (D70.-)

Related Child Codes

Official

D61.0Constitutional aplastic anemia

D61.1Drug-induced aplastic anemia

D61.2Aplastic anemia due to other external agents

D61.3Idiopathic aplastic anemia

D61.8Other specified aplastic anemias and other bone marrow failure syndromes

Includes

Official

ICD-10-CM does not list Includes notes for D61.9 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for D61.9 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for D61.9 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for D61.9 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for D61.9 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Document bone marrow biopsy findings showing marrow hypocellularity.

Record complete blood count values with all three cell lines.

Include the diagnostic workup performed to determine etiology: medication review, toxin exposure history, viral serologies, autoimmune markers, and genetic testing when indicated.

Submit a provider query to specify the type or cause of aplastic anemia.

MEAT Support

HCC Buddy guidance

Document bone marrow biopsy findings showing marrow hypocellularity.

Record complete blood count values with all three cell lines.

Include the diagnostic workup performed to determine etiology: medication review, toxin exposure history, viral serologies, autoimmune markers, and genetic testing when indicated.

Submit a provider query to specify the type or cause of aplastic anemia.

Audit Caution

HCC Buddy guidance

This unspecified code should be a temporary designation while workup is pending -

follow up to determine if a more specific code is appropriate. Do not confuse aplastic anemia with other causes of pancytopenia (nutritional deficiency, hypersplenism, myelodysplastic syndrome). Unspecified codes face the highest audit scrutiny in risk adjustment reviews. Document clearly in the medical record why a more specific diagnosis cannot be assigned if this code must persist.

Common Mistakes

HCC Buddy guidance

D61.1 (Drug-induced aplastic anemia), D61.2 (Aplastic anemia due to other external agents), and D61.3 (Idiopathic aplastic anemia) are more specific acquired forms.

D61.0x codes cover constitutional (inherited) forms.

D61.818 (Other pancytopenia) may be used when pancytopenia is present without confirmed aplastic anemia diagnosis.

D64.9 (Anemia, unspecified) is even less specific and does not convey the aplastic mechanism.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is D61.9 an HCC code?

Yes. D61.9 maps to Severe Hematological Disorders under the V24 model but is not retained in V28.

HCC Category Mapping

V24HCC 46, Severe Hematological Disorders

0.666

ESRDHCC 46, Severe Hematological Disorders

0.000

RxHCCHCC 96, Hemolytic and Aplastic Anemias

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for D61.9

For D61.9to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed D61.9 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

D61.9 is the ICD-10-CM diagnosis code for aplastic anemia, unspecified. A serious condition where the bone marrow fails to produce enough blood cells, but the specific cause is not documented or identified. D61.9 sits in the ICD-10-CM chapter for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (d50-d89), within the section covering aplastic and other anemias and other bone marrow failure syndromes (d60-d64).

Under the older CMS-HCC V24 model, D61.9 maps to Severe Hematological Disorders (HCC 46) with a community, non-dual, aged base RAF weight of 0.666. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

This is a default code; attempt to determine and code the specific type of aplastic anemia when possible. Because D61.9 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for D61.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a default code; attempt to determine and code the specific type of aplastic anemia when possible
•Query the provider if the cause can be identified from clinical documentation

Clinical Significance

Aplastic anemia, unspecified is a nonspecific code indicating bone marrow failure with inadequate blood cell production where the documentation does not specify the cause, type, or characteristics of the aplastic anemia. This code should trigger a comprehensive documentation review and provider query, as the cause of aplastic anemia (drug-induced, idiopathic, constitutional, or secondary to external agents) has critical implications for treatment selection, prognosis, and genetic counseling when hereditary forms are involved.

Documentation Requirements

✓Document bone marrow biopsy findings showing marrow hypocellularity.
✓Record complete blood count values with all three cell lines.
✓Include the diagnostic workup performed to determine etiology: medication review, toxin exposure history, viral serologies, autoimmune markers, and genetic testing when indicated.
✓Submit a provider query to specify the type or cause of aplastic anemia.
✓Document disease severity classification and current treatment approach.

Commonly Confused Codes

•D61.1 (Drug-induced aplastic anemia), D61.2 (Aplastic anemia due to other external agents), and D61.3 (Idiopathic aplastic anemia) are more specific acquired forms.
•D61.0x codes cover constitutional (inherited) forms.
•D61.818 (Other pancytopenia) may be used when pancytopenia is present without confirmed aplastic anemia diagnosis.
•D64.9 (Anemia, unspecified) is even less specific and does not convey the aplastic mechanism.