D61.3
BillableIdiopathic aplastic anemia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D61.3 an HCC code?
Yes. D61.3 maps to Acquired Hemolytic, Aplastic, and Sideroblastic Anemias under the CMS-HCC V28 risk adjustment model (and Severe Hematological Disorders under V24).
HCC Category Mapping
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 D61.3
For D61.3to 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 D61.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D61.3 is the ICD-10-CM diagnosis code for idiopathic aplastic anemia. A serious condition where the bone marrow fails to produce blood cells for unknown reasons, with no identifiable cause or trigger. D61.3 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 CMS-HCC V28 risk adjustment model, D61.3 maps to Acquired Hemolytic, Aplastic, and Sideroblastic Anemias (HCC 109) with a community, non-dual, aged base RAF weight of 1.144. Under the older CMS-HCC V24 model, D61.3 maps to Severe Hematological Disorders (HCC 46) with a community, non-dual, aged base RAF weight of 1.372. 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.
Use this code only after ruling out drug-induced, external agent-related, and other identifiable causes through thorough clinical evaluation. Because D61.3 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 D61.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only after ruling out drug-induced, external agent-related, and other identifiable causes through thorough clinical evaluation
- •Document the diagnostic workup performed to exclude secondary causes of aplastic anemia
Clinical Significance
Idiopathic aplastic anemia is the most common form of acquired aplastic anemia, accounting for approximately 65-70% of cases, where extensive diagnostic evaluation fails to identify a causative drug, toxin, infection, or underlying disease. The pathogenesis is believed to involve immune-mediated destruction of hematopoietic stem cells by autoreactive T lymphocytes, which is supported by the frequent response to immunosuppressive therapy. Disease severity ranges from moderate to very severe and determines whether initial treatment is immunosuppressive therapy (antithymocyte globulin plus cyclosporine) or allogeneic stem cell transplantation.
Documentation Requirements
- ✓Document that thorough evaluation has excluded identifiable causes including drug exposure, toxin exposure, viral infections (hepatitis, Epstein-Barr virus, human immunodeficiency virus), autoimmune diseases, and congenital bone marrow failure syndromes.
- ✓Record complete blood count, bone marrow biopsy showing hypocellularity with fat replacement, and disease severity classification using Camitta criteria (absolute neutrophil count, platelet count, reticulocyte count).
- ✓Document treatment with immunosuppressive therapy or transplant status and response to treatment.
Commonly Confused Codes
- •D61.1 (Drug-induced aplastic anemia) is used when a causative drug is identified.
- •D61.2 (Aplastic anemia due to other external agents) applies to identified environmental causes.
- •D61.09 (Other constitutional aplastic anemia) is for inherited forms.
- •D61.9 (Aplastic anemia, unspecified) is less specific and does not convey that an evaluation was performed.
- •D46.x (Myelodysplastic syndromes) may present similarly and requires bone marrow morphology and cytogenetics to differentiate.