D59.9 ICD-10-CM Code: Acquired hemolytic anemia, unspecified
D59.9 maps to CMS-HCC V28 109. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools
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FY 2026 Apr update / Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) / Hemolytic anemias (D55-D59)
D59.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAcquired hemolytic anemia, unspecified
A condition where red blood cells are destroyed faster than the body can replace them, but the specific cause is not identified or documented.
Buddy Insight
Acquired hemolytic anemia, unspecified is assigned when a patient has confirmed acquired hemolytic anemia but the documentation does not identify the specific type or cause.
CMS-HCC V28
MappedHCC 109
Code-level coefficient reference
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 069
Code-level coefficient reference
ESRD/PACE
MappedHCC 46
Code-level coefficient reference
RXHCC
MappedHCC 96
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Idiopathic hemolytic anemia, chronic
Excludes 2
Official- autoimmune disease (systemic) NOS (M35.9)Inherited from D50-D89
- certain conditions originating in the perinatal period (P00-P96)Inherited from D50-D89
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from D50-D89
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from D50-D89
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from D50-D89
- human immunodeficiency virus [HIV] disease (B20)Inherited from D50-D89
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from D50-D89
- neoplasms (C00-D49)Inherited from D50-D89
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from D50-D89
Related Codes
Includes
OfficialNo Includes notes are included in this display for D59.9. Check the code and parent instructions in the Code Book.
Excludes 1
OfficialNo Excludes 1 notes are included in this display for D59.9. Check the code and parent instructions in the Code Book.
Code First
OfficialNo Code First sequencing instructions are included in this display for D59.9. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for D59.9. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for D59.9. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is D59.9 an HCC code?
Yes. D59.9 (Acquired hemolytic anemia, unspecified) maps to HCC 109, Acquired Hemolytic, Aplastic, and Sideroblastic Anemias under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.144. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: D59.9 is billable and maps to V28 HCC 109, Acquired Hemolytic, Aplastic, and Sideroblastic Anemias. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- D59.9
- Description
- Acquired hemolytic anemia, unspecified
- HCC (V28)
- HCC 109 — Acquired Hemolytic, Aplastic, and Sideroblastic Anemias
- RAF reference coefficient
- 1.144
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work D59.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for D59.9
For D59.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
D59.9 is the ICD-10-CM diagnosis code for acquired hemolytic anemia, unspecified. A condition where red blood cells are destroyed faster than the body can replace them, but the specific cause is not identified or documented. D59.9 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 hemolytic anemias (d55-d59).
Under the CMS-HCC V28 risk adjustment model, D59.9 maps to Acquired Hemolytic, Aplastic, and Sideroblastic Anemias (HCC 109) with a source-labeled community, non-dual, aged reference coefficient of 1.144. No V24 mapping is shown for D59.9; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Use this code only when the type of hemolytic anemia cannot be determined; review documentation for more specific hemolytic anemia codes (D59.0-D59.8). For D59.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for D59.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Acquired hemolytic anemia, unspecified is assigned when a patient has confirmed acquired hemolytic anemia but the documentation does not identify the specific type or cause. This code indicates a diagnostic workup gap, as the immune vs non-immune mechanism, causative agent, and underlying etiology remain undetermined. Providers should be queried to clarify the hemolysis mechanism (autoimmune vs mechanical vs drug-induced) and any identifiable triggers, as this information directly impacts treatment decisions.
Documentation Requirements
- ✓Document laboratory evidence confirming hemolytic anemia (elevated lactate dehydrogenase, elevated indirect bilirubin, low haptoglobin, reticulocytosis, peripheral smear findings).
- ✓Record hemoglobin values and transfusion history.
- ✓Include direct antiglobulin (Coombs) test results to distinguish immune from non-immune hemolysis.
- ✓Document what diagnostic workup has been performed and what is pending.
- ✓Submit a provider query requesting specification of the hemolysis type and cause.
Commonly Confused Codes
- •D59.0-D59.8 provide more specific acquired hemolytic anemia codes.
- •D58.9 (Hereditary hemolytic anemia, unspecified) is for inherited rather than acquired conditions.
- •D64.9 (Anemia, unspecified) does not specify hemolytic mechanism and is even less specific.
- •D59.10 (Autoimmune hemolytic anemia, unspecified) should be used when autoimmune etiology is confirmed but the subtype is unknown.