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This Clinical Documentation Guide (CDG) provides AAPC/AHIMA-credentialed coders and clinical documentation integrity (CDI) specialists with comprehensive coding, clinical, and documentation guidance for anemias — with a focus on blood loss anemia — and polycythemia. Content reflects FY2026 ICD-10-CM guidelines (effective October 1, 2025 – September 30, 2026) and incorporates current clinical, risk adjustment, and CDI query standards. Use this guide to ensure accurate diagnosis code assignment, defensible documentation, and appropriate CDI query triggers across all inpatient and outpatient care settings.
1. Definition
Anemia is a condition in which the number of red blood cells (RBCs) or the hemoglobin concentration within them is lower than normal, impairing the blood’s ability to carry adequate oxygen to the body’s tissues. The World Health Organization (WHO) defines anemia as hemoglobin below 13 g/dL in adult males, below 12 g/dL in non-pregnant adult females, and below 11 g/dL in pregnant women. Anemia may result from blood loss, decreased RBC production, or increased RBC destruction, and its clinical significance varies widely from asymptomatic laboratory findings to life-threatening hemorrhagic shock.
Anemia due to blood loss — the primary focus of this guide — is subdivided by acuity:
- Acute posthemorrhagic anemia (D62): Anemia resulting from sudden, significant blood loss (e.g., trauma, surgical hemorrhage, GI bleeding event, ruptured aneurysm). The rapid decline in circulating RBC mass outpaces compensatory erythropoiesis. Clinical criteria require physician documentation linking anemia to acute blood loss, supported by a sustained hemoglobin/hematocrit decline, as outlined in AHA Coding Clinic, 3Q 2019.
- Iron deficiency anemia secondary to blood loss, chronic (D50.0): Long-standing blood loss (e.g., chronic GI bleeding, heavy menstrual periods, esophageal varices) depletes iron stores over time, resulting in microcytic, hypochromic anemia.
Anemia in chronic disease encompasses several distinct etiologies: anemia associated with neoplastic disease (D63.0), anemia in chronic kidney disease (D63.1), anemia in other chronic diseases (D63.8), and drug-induced anemia (D64.81). Each requires documentation of the underlying condition and its causal relationship to the anemia.
Polycythemia is the opposite condition — an abnormal increase in the total red blood cell mass, leading to elevated hematocrit and blood viscosity. It is classified as primary (polycythemia vera, D45), secondary (reactive elevation from hypoxia, EPO excess, or other causes; D75.1), familial/hereditary (D75.0), or neonatal (P61.1). Polycythemia vera is classified as a neoplasm of uncertain behavior by ICD-10-CM and carries significant risk adjustment weight.
2. Alternative Terminology
| Formal / Clinical Term | Colloquial / Lay / Alternative Names |
|---|---|
| Acute posthemorrhagic anemia (D62) | Acute blood loss anemia; hemorrhagic anemia; post-surgical anemia; traumatic anemia; blood loss anemia, acute |
| Iron deficiency anemia secondary to blood loss, chronic (D50.0) | Chronic blood loss anemia; iron deficiency anemia from GI bleed; anemia from menorrhagia; chronic hemorrhagic anemia |
| Anemia in neoplastic disease (D63.0) | Cancer-related anemia; anemia of malignancy; tumor-associated anemia; chemotherapy-related anemia (partial overlap with D64.81) |
| Anemia in chronic kidney disease (D63.1) | Renal anemia; CKD anemia; anemia of renal failure; EPO-deficiency anemia |
| Anemia in other chronic diseases (D63.8) | Anemia of chronic disease (ACD); anemia of inflammation; ACI (anemia of chronic inflammation) |
| Drug-induced anemia (D64.81) | Medication-caused anemia; chemotherapy-induced anemia; NSAID-related anemia; antineoplastic anemia |
| Anemia, unspecified (D64.9) | Low blood count (non-specific); anemia NOS; blood dyscrasia (lay) |
| Polycythemia vera (D45) | PV; primary polycythemia; Vaquez disease; Osler-Vaquez disease; erythrocythemia (historical) |
| Secondary polycythemia (D75.1) | Reactive polycythemia; secondary erythrocytosis; altitude polycythemia; stress polycythemia |
| Familial erythrocytosis (D75.0) | Hereditary polycythemia; congenital polycythemia; familial polycythemia |
| Neonatal polycythemia (P61.1) | Neonatal hyperviscosity syndrome; twin-to-twin transfusion polycythemia; placental transfusion polycythemia |
3. Signs & Symptoms
Anemia (Blood Loss)
Clinical presentation depends on acuity and severity of blood loss. Per StatPearls (NCBI), anemia due to blood loss presents with:
- Fatigue and generalized weakness — most common presenting symptom; disproportionate to activity level
- Pallor — particularly of conjunctiva, nail beds, and palmar creases
- Tachycardia and palpitations — compensatory response to reduced oxygen-carrying capacity
- Dyspnea on exertion — worsening with progressive anemia
- Dizziness/lightheadedness/syncope — especially with acute blood loss and volume depletion
- Hypotension — in acute hemorrhagic cases; may progress to hemorrhagic shock
- Tachypnea — compensatory respiratory response
- Decreased urine output — in hypovolemic states from acute blood loss
- Koilonychia (spoon nails) and glossitis — classic signs of chronic iron deficiency anemia
- Pica — craving for non-food items (ice, clay, dirt) seen in severe iron deficiency
Polycythemia
- Pruritus after bathing (aquagenic pruritus) — characteristic of polycythemia vera; present in ~40% of PV patients
- Plethora (facial redness/ruddy complexion) — due to increased RBC mass and skin hyperemia
- Headache, dizziness, and visual disturbances — from hyperviscosity and reduced cerebral blood flow
- Splenomegaly — palpable in 70–90% of PV patients from extramedullary hematopoiesis
- Thrombotic events (DVT, stroke, MI, Budd-Chiari syndrome) — major complications from hyperviscosity
- Erythromelalgia — burning pain/redness of hands and feet due to platelet-mediated microvascular occlusion
- Gout — from elevated uric acid due to increased cell turnover
- Hypertension — common comorbidity in PV
- Bleeding tendency — paradoxically, despite elevated platelets, qualitative platelet dysfunction can cause GI bleeding
Signs and symptoms that are routinely associated with a confirmed diagnosis of anemia or polycythemia (e.g., tachycardia, fatigue, pallor with anemia; headache, pruritus with PV) are not coded separately per ICD-10-CM Official Guidelines Section I.C.3. However, complications such as thrombotic events in PV are coded additionally when clinically documented.
4. Differential Diagnosis
| Condition | Key Distinguishing Features | Primary ICD-10-CM Code |
|---|---|---|
| Acute posthemorrhagic anemia (D62) | Sudden, significant blood loss; acute Hgb/Hct drop; physician documentation of acute blood loss; may include trauma, GI hemorrhage, surgery | D62 |
| Iron deficiency anemia, chronic blood loss (D50.0) | Low ferritin, low serum iron, high TIBC; microcytic hypochromic RBCs; documented chronic blood loss source (GI, menstrual) | D50.0 |
| Iron deficiency anemia, unspecified (D50.9) | Iron deficiency without documented blood loss etiology; dietary or absorption cause | D50.9 |
| Anemia of CKD (D63.1) | Normocytic normochromic; low EPO; elevated creatinine/BUN; CKD documented by provider; requires coding CKD first | D63.1 + CKD code |
| Anemia of neoplastic disease (D63.0) | Associated malignancy documented; may overlap with chemo-induced anemia; provider must document causal link | Malignancy first + D63.0 |
| Chemotherapy-induced anemia (D64.81) | Temporally linked to antineoplastic therapy; distinct from D63.0; drug adverse effect codes required | D64.81 + adverse effect code |
| Vitamin B12 deficiency anemia (D51.x) | Macrocytic/megaloblastic; elevated MCV; low B12; may have neurologic symptoms (subacute combined degeneration) | D51.x |
| Folate deficiency anemia (D52.x) | Macrocytic; low folate; no neurologic symptoms; often dietary or drug-induced (methotrexate) | D52.x |
| Aplastic anemia (D61.x) | Pancytopenia (all cell lines low); bone marrow biopsy showing hypocellularity; may be constitutional or acquired | D61.x |
| Hemolytic anemia (D55–D59) | Elevated LDH, low haptoglobin, elevated indirect bilirubin, reticulocytosis; positive Coombs in autoimmune type | D55–D59.x |
| Polycythemia vera (D45) | JAK2 V617F mutation; elevated Hgb/Hct beyond threshold; low EPO; splenomegaly; meets WHO 2016/2022 criteria | D45 |
| Secondary polycythemia (D75.1) | Elevated EPO from COPD, sleep apnea, renal tumor, high altitude, EPO doping; JAK2 negative; normal/high EPO | D75.1 |
| Relative/spurious polycythemia | Normal RBC mass; reduced plasma volume (dehydration, diuretics, Gaisbock syndrome); not coded as polycythemia | Underlying cause |
5. Clinical Indicators for Coders/CDI
| Clinical Indicator | Significance for Coding/CDI |
|---|---|
| Hemoglobin < 13.6 g/dL (male) or < 11.9 g/dL (female) | Meets WHO diagnostic threshold for anemia — query provider if not documented as a diagnosis |
| Acute drop in Hgb ≥ 1.0–2.0 g/dL or Hct ≥ 3–6% | Supports acute blood loss anemia (D62) — verify physician documented acute blood loss as cause per AHIMA CDI standards |
| Blood transfusion ordered/administered | Strong CDI trigger — query for anemia type and acuity; transfusion alone is NOT sufficient to assign D62 without physician diagnosis |
| Intraoperative/post-operative blood loss documented in operative note | Must be ≥ 300 mL significant loss for consideration; physician must link to anemia diagnosis to code D62 |
| Low ferritin + low serum iron + high TIBC | Classic iron deficiency triad — differentiate chronic blood loss (D50.0) from dietary iron deficiency (D50.9) based on documentation |
| Hemoglobin A1c correlation with RBC lifespan | Falsely low A1c may indicate hemolytic anemia or blood loss anemia — note for comorbidity coding |
| EPO therapy initiated (J0881/J0885) | Strong indicator of anemia of CKD (D63.1) or cancer-related anemia (D63.0); ensure underlying condition coded first |
| IV iron infusion ordered (J1750, J1439, J1437) | Indicates iron deficiency anemia; query for cause (blood loss vs. dietary vs. CKD-related) |
| JAK2 V617F mutation positive | Diagnostic of polycythemia vera (D45) — do NOT code as secondary polycythemia |
| Elevated Hgb (> 16.5 g/dL male / > 16 g/dL female) + splenomegaly + low EPO | WHO 2016/2022 major criteria for PV — CDI should ensure D45 is documented, not generic “elevated hemoglobin” |
| Documentation of “anemia” without type/cause in cancer patient | Query to differentiate: anemia in neoplastic disease (D63.0), chemotherapy-induced anemia (D64.81), or iron deficiency from GI bleeding (D50.0/D62) |
| Post-operative patient with declining Hgb, no stated cause | Classic CDI trigger for acute blood loss anemia — do NOT default to D64.9; query surgeon to document causal link to intraoperative/postoperative blood loss |
Post-surgical declining hemoglobin: When a patient has documented blood loss during surgery ≥ 300 mL, receives a transfusion, and has a sustained hemoglobin drop, but the physician has not documented a diagnosis of anemia, a CDI query is warranted. Per AHA Coding Clinic 3Q 2019, coders cannot independently assign D62 without physician documentation explicitly linking the anemia to acute blood loss. The query should present multiple-choice options: (1) Acute posthemorrhagic anemia, (2) Anemia related to chronic blood loss, (3) Anemia, unspecified, (4) Clinically insignificant — not a diagnosis for this encounter.
6. Anatomy & Pathophysiology
Erythropoiesis and Red Blood Cell Physiology
Red blood cells (erythrocytes) are produced in the bone marrow via erythropoiesis, a process regulated primarily by erythropoietin (EPO), a glycoprotein hormone produced by peritubular cells of the renal cortex in response to tissue hypoxia. Normal RBC lifespan is approximately 120 days; aged or damaged cells are cleared by splenic macrophages. The average adult has approximately 5 million RBCs/μL and 14–17 g/dL hemoglobin (males) or 12–15 g/dL (females), per StatPearls.
Pathophysiology of Blood Loss Anemia
In acute hemorrhage, intravascular volume and RBC mass fall simultaneously. Initially, hematocrit may appear normal due to proportional plasma loss; over 24–72 hours, compensatory hemodilution from fluid shifts and volume replacement causes the true extent of RBC loss to manifest as a measured anemia. The bone marrow responds with increased erythropoiesis (reticulocytosis) within 3–5 days, but cannot replace acute losses rapidly.
In chronic blood loss, the sustained but slower hemorrhage gradually depletes iron stores (ferritin → serum iron → bone marrow iron → TIBC elevation → hemoglobin fall), producing the classic microcytic hypochromic pattern of iron deficiency anemia (D50.0). Common chronic sources include peptic ulcer disease, colorectal polyps/cancer, celiac disease, hookworm infestation, and menorrhagia.
Pathophysiology of Polycythemia Vera
Polycythemia vera is a clonal myeloproliferative neoplasm driven by an acquired somatic mutation in the JAK2 gene — the JAK2 V617F point mutation is present in >95% of PV patients, as documented by the NCCN Guidelines for Myeloproliferative Neoplasms. This mutation results in constitutive activation of the JAK-STAT signaling pathway, causing EPO-independent proliferation of erythroid precursors. The resulting increase in RBC mass elevates blood viscosity, promoting thrombosis. Long-term, PV may progress to myelofibrosis (spent phase) or acute myeloid leukemia (AML) in ~10–20% of patients over 20 years.
Pathophysiology of Secondary Polycythemia
Secondary polycythemia (D75.1) reflects an appropriate physiological response to chronic hypoxia (COPD, OSA, cyanotic heart disease, high altitude) or inappropriate EPO overproduction (renal cell carcinoma, hepatocellular carcinoma, cerebellar hemangioblastoma). Unlike PV, EPO levels are elevated (or inappropriately normal), JAK2 is negative, and thrombotic risk is generally lower. Correction of the underlying cause typically resolves the erythrocytosis.
7. Medication Impact / Treatment
Anemia Treatment
- Blood transfusion (PRBC): First-line for symptomatic acute anemia; typically indicated when Hgb < 7–8 g/dL or with cardiovascular compromise. Coded with CPT 36430 and HCPCS P9011 (PRBCs) or P9016 (leukocyte-reduced RBCs).
- Oral iron supplementation: First-line for iron deficiency anemia when GI tolerated (ferrous sulfate 325 mg TID). No specific CPT or HCPCS; pharmacy dispensed.
- IV iron therapy: Used when oral iron is intolerable or malabsorbed, or in CKD patients on dialysis. Key HCPCS codes include J1750 (iron dextran), J1439 (ferric carboxymaltose, Injectafer), and J1437 (iron sucrose). Administration coded with CPT 96372 (IV/IM injection) or appropriate infusion code.
- Erythropoiesis-stimulating agents (ESAs): Epoetin alfa (J0881 per 1,000 units) and darbepoetin alfa (J0885 per 25 mcg) stimulate RBC production. Indicated for anemia of CKD (D63.1) and in select cancer-related anemias (D63.0); NOT indicated for iron deficiency or acute blood loss anemia. CMS LCD L34375 governs Medicare ESA coverage requirements — documentation must establish Hgb < 10 g/dL and clinical indication.
- Drug-induced anemia cessation: When D64.81 applies, the causative agent should be identified; adverse effect codes from T36–T50 (with 5th/6th character 5) are added per ICD-10-CM instructions.
ESA use does NOT automatically indicate anemia of CKD. ESAs can be used in cancer-related anemia (D63.0) and myelodysplastic syndromes. Coders and CDI must review all clinical documentation — not just medication orders — to select the correct anemia etiology code. An ESA order alone is insufficient to assign D63.1 without physician documentation of CKD and its causal link to anemia.
Polycythemia Treatment
- Phlebotomy (therapeutic): First-line for PV to maintain hematocrit < 45%. CPT 36415 (venipuncture) may apply; document as therapeutic phlebotomy for blood viscosity management.
- Cytoreductive therapy: Hydroxyurea (first-line cytoreduction for high-risk PV), ruxolitinib (JAK1/2 inhibitor for hydroxyurea-intolerant/refractory PV per NCCN), interferon-alpha. Reported with appropriate evaluation/management codes.
- Aspirin (low-dose): Reduces thrombotic risk in PV; typically 81–100 mg/day.
- Splenectomy: Occasionally performed for PV with massive, symptomatic splenomegaly or in late-stage myelofibrotic transformation. CPT codes 38100 (splenectomy total, laparotomy approach) or 38101 (partial), 38102 (total, en bloc), 38115 (repair of ruptured spleen). More commonly performed for hereditary hemolytic anemias (e.g., hereditary spherocytosis) than for PV.
- Partial exchange transfusion: Used in neonatal polycythemia (P61.1) to reduce hematocrit safely.
Preview ends here. The full guide continues with FY2026 ICD-10-CM code sets, CPT surgical coding, MS-DRG mapping, reimbursement guidance, CDI query templates, and an audit checklist — all available to CCO Members.
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8. ICD-10-CM Guidelines (FY2026)
The following ICD-10-CM Official Guidelines (FY2026) govern coding of anemias and polycythemia. All guidance is effective October 1, 2025, per CMS ICD-10-CM FY2026 files.
Acute vs. Chronic Blood Loss Anemia
ICD-10-CM classifies acute blood loss anemia to D62 (Acute posthemorrhagic anemia) and chronic blood loss anemia to D50.0 (Iron deficiency anemia secondary to blood loss, chronic). An Excludes1 note appears at each code cross-referencing the other, confirming they are mutually exclusive. Per AHA Coding Clinic, 3Q 2019: “If both acute and chronic blood loss anemia are documented, assign only the code for acute blood loss anemia (D62).” Coders must not assign both D62 and D50.0 simultaneously.
Anemia Associated with Underlying Disease (D63.x)
When anemia is caused by a chronic disease, the ICD-10-CM tabular instruction at D63 directs “Code first” the underlying disease (e.g., neoplasm, CKD). The anemia code (D63.0, D63.1, or D63.8) is then assigned as an additional code. The provider must explicitly document the causal relationship between the underlying condition and the anemia — coders may NOT assume linkage without physician documentation, per ICD-10-CM Official Guidelines Section I.B.5.
Drug-Induced Anemia (D64.81)
When anemia is drug-induced, assign D64.81 plus an adverse effect code from categories T36–T50 with the 6th character “5” to identify the drug. The ICD-10-CM FY2026 tabular instruction at D64.81 reads: “Use additional code for adverse effect, if applicable, to identify drug (T36–T50 with fifth or sixth character 5).” Note: D64.81 is distinct from D6481 (anemia due to antineoplastic chemotherapy), which has its own instructional notes in the tabular.
Polycythemia Vera (D45) Coding Guidance
D45 is classified in ICD-10-CM Chapter 2 (Neoplasms) under “Neoplasms of uncertain behavior.” Per GuideWell provider documentation guidance, documentation must identify the specific type of polycythemia (vera vs. secondary vs. familial). Coders may NOT default to D45 based solely on an abnormal lab value — the provider must document the diagnosis of polycythemia vera. The JAK2 mutation, low EPO level, and bone marrow biopsy findings, while clinically confirmatory, must be translated into a physician diagnosis.
Sequencing — Anemia as Principal vs. Secondary Diagnosis
- When a patient is admitted for management of anemia and the anemia is the condition chiefly responsible for the admission, anemia is the principal diagnosis.
- When anemia is a complication or comorbidity of another principal condition (e.g., GI bleed, malignancy, CKD), the underlying condition is the principal diagnosis, and anemia is a secondary diagnosis — provided it meets the UHDDS definition of an additional diagnosis (affects management, extends LOS, or requires additional workup).
- Per Livanta Claims Review Advisor: “Hospitals frequently re-sequence anemia to the principal diagnosis in place of the hemorrhage code… [without] supporting documentation.” This is a common audit target.
RAC auditors actively target D62 coded without adequate physician documentation of acute blood loss causality. A post-surgical patient with a declining Hgb who receives a transfusion does not automatically meet criteria for D62 — the surgeon must document that the anemia is due to acute blood loss from the surgical procedure. Review operative notes, anesthesia records, and discharge summary for explicit physician documentation before assigning D62. Per Health Information Associates CDI guidance, both physician documentation of acute blood loss AND laboratory evidence (sustained Hgb/Hct decline) are required.
9. ICD-10-CM Code Set (FY2026)
| Code | Description | Key Notes / Documentation Requirements |
|---|---|---|
| D50.0 | Iron deficiency anemia secondary to blood loss (chronic) | Chronic blood loss documented (GI bleed, menorrhagia, ulcer). Excludes1: D62. Low ferritin/iron, high TIBC expected on labs. Microcytic, hypochromic RBCs. |
| D50.8 | Other iron deficiency anemias | Iron deficiency anemia not due to chronic blood loss or dietary deficiency; specified as iron deficiency not elsewhere classified. |
| D50.9 | Iron deficiency anemia, unspecified | Use only when cause of iron deficiency is not documented. Avoid if blood loss, dietary, or absorption etiology is evident — specificity reduces denials. |
| D62 | Acute posthemorrhagic anemia | Sudden blood loss; physician must document “acute blood loss anemia.” Excludes1: D50.0. If both acute and chronic documented, assign only D62 (AHA Coding Clinic 3Q 2019). MCC in MS-DRG grouper. |
| D63.0 | Anemia in neoplastic disease | Code first neoplasm. Provider must document causal link. Excludes anemia due to antineoplastic chemotherapy (D64.81). Valid for HCC v28 HCC 109 when neoplasm maps separately. |
| D63.1 | Anemia in chronic kidney disease | Code first CKD stage (N18.x). CKD must be documented as cause. EPO prescribing does not alone suffice — physician documentation required. |
| D63.8 | Anemia in other chronic diseases classified elsewhere | Code first the underlying chronic disease (e.g., rheumatoid arthritis, hypothyroidism, IBD). Used for anemia of chronic disease/inflammation not covered by D63.0 or D63.1. |
| D64.1 | Secondary sideroblastic anemia due to disease | Acquired sideroblastic anemia from myelodysplasia or other non-toxic underlying disease. Maps to HCC 109 in v28. |
| D64.81 | Anemia due to antineoplastic chemotherapy | Use additional adverse effect code (T45.1x5x). Distinct from D63.0. Note: code description uses “antineoplastic” specifically — not all chemotherapy agents qualify; document agent. |
| D64.9 | Anemia, unspecified | Last resort; use only when type of anemia is truly undocumented after clinical review. High denial risk with Medicare. CDI query should be pursued before defaulting to D64.9. |
| D45 | Polycythemia vera | Chapter 2 (Neoplasms of uncertain behavior). JAK2 V617F mutation present in >95%. Low serum EPO. High-risk for thrombosis. Document specific diagnosis — do NOT code from lab values alone. Maps to HCC 18 (Myeloproliferative Disorders) in v28. |
| D75.0 | Familial erythrocytosis | Hereditary; often presents in childhood/adolescence. Normal or elevated EPO; JAK2 negative. Genetic testing may confirm. |
| D75.1 | Secondary polycythemia | Reactive/acquired; elevated or normal EPO from hypoxia (COPD, OSA, altitude) or EPO-producing tumors. JAK2 negative. Document underlying cause; code additionally if appropriate. |
| P61.1 | Polycythemia neonatorum | Newborn; hematocrit > 65%; often twin-twin transfusion, placental transfusion, maternal diabetes. Managed with partial exchange transfusion. Coded only for newborn patients. |
| D61.01 | Constitutional (pure) red blood cell aplasia | Diamond-Blackfan anemia; pure red cell aplasia. Maps to HCC 109 in v28. High RAF impact. |
| D61.810 | Antineoplastic chemotherapy induced pancytopenia | All three cell lines suppressed by chemo. Maps to HCC 109 in v28. Code adverse effect (T45.1x5x). |
| D61.818 | Other pancytopenia | Pancytopenia from non-specified causes. Maps to HCC 109 in v28. |
| D75.81 | Myelofibrosis | Post-PV/ET myelofibrosis; primary myelofibrosis. Progressive bone marrow fibrosis. Maps to HCC 18 in v28. High RAF. May require bone marrow biopsy documentation. |
The D50–D53 range covers nutritional and iron-related anemias. D51.x codes cover vitamin B12 deficiency anemias (intrinsic factor deficiency, dietary B12 deficiency); D52.x covers folate deficiency anemias (dietary and drug-induced). D53.x includes protein deficiency anemia (D53.0), megaloblastic anemias NEC (D53.1), and scorbutic anemia (D53.2). Hemolytic anemias (D55–D59) are covered separately — hereditary hemolytic anemias (D55–D58) and acquired hemolytic anemias (D59.x). Aplastic anemias (D60–D61) require highly specific documentation of etiology for accurate subcode selection and maximum HCC risk adjustment capture.
10. Indexing
The following index entries are taken from the FY2026 ICD-10-CM Alphabetic Index. Coders must always verify index entries against the Tabular List before assigning codes.
| Index Term / Path | Code(s) Found |
|---|---|
| Anemia → blood loss → acute | D62 |
| Anemia → blood loss → chronic | D50.0 |
| Anemia → due to → blood loss → acute | D62 |
| Anemia → due to → blood loss → chronic | D50.0 |
| Anemia → due to → chronic kidney disease | D63.1 |
| Anemia → due to → neoplastic disease | D63.0 |
| Anemia → drug-induced NEC | D64.81 |
| Anemia → iron deficiency → due to blood loss (chronic) | D50.0 |
| Anemia → iron deficiency → unspecified | D50.9 |
| Anemia → posthemorrhagic (chronic) | D50.0 |
| Anemia → posthemorrhagic (acute) | D62 |
| Anemia → sideroblastic → secondary → due to disease | D64.1 |
| Anemia → unspecified | D64.9 |
| Polycythemia → vera | D45 |
| Polycythemia → secondary | D75.1 |
| Polycythemia → familial | D75.0 |
| Polycythemia → neonatorum | P61.1 |
| Erythrocytosis → familial | D75.0 |
| Erythrocytosis → secondary | D75.1 |
| Myelofibrosis | D75.81 |
| Pancytopenia → antineoplastic chemotherapy-induced | D61.810 |
11. CPT (2026)
| Code | Description | Global Period | Notes |
|---|---|---|---|
| 85025 | Blood count; complete (CBC), automated, and automated differential WBC count | XXX | Primary diagnostic tool for anemia and polycythemia. Provides Hgb, Hct, MCV, MCHC, RDW, WBC, platelets. Order at initial workup and monitoring. |
| 85027 | Blood count; complete (CBC), automated | XXX | CBC without automated differential. Less specific than 85025; used when differential count not clinically needed. |
| 85610 | Prothrombin time (PT/INR) | XXX | Relevant in hemorrhagic anemia workup to assess coagulopathy. Abnormal PT may indicate concurrent coagulation disorder. |
| 36415 | Collection of venous blood by venipuncture | XXX | Standard blood draw for lab studies; also used for therapeutic phlebotomy documentation in polycythemia vera management. Bill with appropriate lab codes. |
| 36430 | Transfusion, blood or blood components | XXX | Covers PRBC transfusion for symptomatic anemia. Report HCPCS supply codes (P9011, P9016) for the blood product in addition to 36430 for the service. |
| 36600 | Arterial puncture, withdrawal of blood for diagnosis | XXX | Arterial blood gas (ABG) — relevant in polycythemia workup to assess oxygen saturation/hypoxia. Use in secondary polycythemia evaluation from pulmonary etiology. |
| 96372 | Therapeutic, prophylactic, or diagnostic injection; subcutaneous or intramuscular | XXX | Used for SC/IM administration of ESAs (epoetin, darbepoetin) or iron (if IM route). Do not use 96372 for IV infusions — use 96365–96368 for IV infusions. |
| 38100 | Splenectomy; total (separate procedure) | 090 | Occasionally performed for massive symptomatic splenomegaly in PV or hereditary hemolytic anemias (spherocytosis). Full laparotomy approach. |
| 38101 | Splenectomy; partial (separate procedure) | 090 | Partial splenectomy preserving splenic function. Less common; may be used in hereditary anemias in young patients. |
| 38102 | Splenectomy; total, en bloc for extensive disease, in conjunction with other procedure (list separately in addition to code for primary procedure) | ZZZ | Add-on code for splenectomy performed as part of a larger oncologic or staging procedure. |
| 38115 | Repair of ruptured spleen (splenorrhaphy) with or without partial splenectomy | 090 | Traumatic splenic injury — may be relevant when polycythemia vera complicates traumatic splenic rupture or in acute hemorrhagic contexts. |
Therapeutic phlebotomy for polycythemia vera is typically reported using CPT 36415 (venipuncture) with documentation specifying the therapeutic intent. Some payers recognize a distinct service for therapeutic phlebotomy. Verify payer-specific guidance, as some payers use CPT 99195 (phlebotomy, therapeutic) which was deleted from the AMA CPT code set; the AMA replaced it with 36415 billed with a modifier. Always check current payer policy and local coverage determinations (LCDs) for therapeutic phlebotomy billing.
12. HCPCS (2026)
| Code | Description | Typical Use / Notes |
|---|---|---|
| J0881 | Injection, darbepoetin alfa, 1 mcg (non-ESRD use) | ESA for anemia of CKD (non-dialysis) and cancer-related anemia. Billed per 1 mcg. Requires diagnosis D63.0 or D63.1 with Hgb < 10 g/dL per CMS LCD L34375. |
| J0885 | Injection, epoetin alfa (for non-ESRD use), 1000 units | ESA for CKD anemia (non-dialysis) and anemia of malignancy. Billed per 1,000 units. Also see J0886 for ESRD use. Coverage requires documented anemia due to qualifying condition; not covered for iron deficiency or acute blood loss. |
| J1750 | Injection, iron dextran, 50 mg | IV iron replacement for iron deficiency anemia when oral iron is contraindicated or ineffective. Most commonly used in CKD and inflammatory bowel disease. Requires premedication protocol due to anaphylaxis risk. |
| J1439 | Injection, ferric carboxymaltose, 1 mg (Injectafer) | High-dose IV iron; allows large single-dose administration. Used in iron deficiency anemia of CKD, heart failure, and cancer patients. Bill per 1 mg; typical dose 750 mg. |
| J1437 | Injection, ferric derisomaltose (Monoferric), 10 mg | Single-dose IV iron infusion; newer formulation allowing up to 1,000 mg per infusion. Check payer coverage; some policies use J1437 for iron sucrose (Venofer) — verify current year assignment. |
| P9010 | Whole blood for transfusion, per unit | Whole blood transfusion (rarely used in modern practice; typically used in massive transfusion protocols or emergency settings). Report with CPT 36430 for the service. |
| P9011 | Whole blood or red blood cells, leukocytes reduced, CMV-tested, each unit | Frequently used for immunocompromised patients (transplant, oncology). Bill in addition to CPT 36430. |
| P9016 | Red blood cells, leukocytes reduced, each unit | Standard leukocyte-reduced PRBCs — most common PRBC product used for routine transfusion. Bill with CPT 36430. Leukoreduction reduces febrile transfusion reactions and CMV transmission risk. |
13. AHA Coding Clinic (Recent Guidance)
| Topic | Guidance / Key Takeaway | Reference |
|---|---|---|
| Acute vs. chronic blood loss anemia — concurrent documentation | When documentation supports both acute and chronic blood loss anemia, assign ONLY D62 (acute posthemorrhagic anemia). D50.0 and D62 have mutual Excludes1 notes. Do NOT assign both simultaneously. | AHA Coding Clinic, 3Q 2019 |
| Acute on chronic blood loss anemia — code selection | In a scenario with active acute GI hemorrhage superimposed on chronic blood loss anemia (e.g., bleeding duodenal ulcer), ICD-10-CM classifies the acute episode to D62. The Excludes1 at both D62 and D50.0 confirms mutual exclusivity — assign only D62 for the acute on chronic presentation. | AHA Coding Clinic, 3Q 2019 |
| Anemia not documented as principal diagnosis by physician | Coders cannot independently designate acute blood loss anemia as the principal diagnosis without physician documentation. If a patient is transfused with a declining Hgb but the physician does not document anemia, coders should not assign D62 independently — a query is required. | ICD-10-CM Official Guidelines, Section I.B; AHA Coding Clinic multiple issues |
| Aplastic anemia and chemotherapy-induced pancytopenia | For aplastic anemia and neutropenic fever due to chemotherapy, assign: D61.810 (chemo-induced pancytopenia) + D70.1 (agranulocytosis secondary to cancer chemotherapy) + R50.81 (fever presenting with conditions classified elsewhere) + adverse effect code. Per Livanta CRA, 2022. | AHA Coding Clinic; CMS Livanta Claims Review Advisor 2022 |
| Polycythemia vera documentation requirement | Coders cannot assign D45 based solely on an elevated hemoglobin value or abnormal CBC. The provider must document the diagnosis of polycythemia vera, with supporting clinical evidence (JAK2 mutation, elevated RBC mass, low EPO). Per GuideWell Coding Spotlight. | ICD-10-CM Official Guidelines Section I.B.2; GuideWell Coding Spotlight 2023 |
| Anemia of chronic disease — “Code first” sequencing | For D63.0, D63.1, and D63.8, the ICD-10-CM tabular includes “Code first” instructions — the underlying condition must be sequenced first. Failure to sequence correctly is a common audit finding. The provider must document the causal relationship between the underlying disease and the anemia. | ICD-10-CM FY2026 Tabular; ICD-10-CM Official Guidelines I.C.3 |
The Excludes1 notes between D62 and D50.0 are frequently misunderstood. An Excludes1 note means the two conditions are mutually exclusive and both codes should never be assigned to the same patient at the same time. If documentation mentions both “acute blood loss anemia” and “chronic iron deficiency anemia,” assign only D62 per AHA Coding Clinic 3Q 2019. Assigning both codes simultaneously is a coding error and will trigger CMS edit rejections.
14. HCC / Risk Adjustment (v28)
The CMS-HCC Model v28 is fully operative for payment year 2026 (100% v28 blend, 0% v24). Key blood disorder HCC categories relevant to this guide are detailed below. RAF coefficients shown are for community-dwelling, non-dual, aged beneficiaries (the most common population).
| ICD-10-CM Code(s) | HCC v28 Category | HCC # | Approx. RAF Coefficient | Documentation Requirement |
|---|---|---|---|---|
| D45 (Polycythemia vera) | Myeloproliferative Disorders and Myelodysplastic Syndromes (Moderate/Severe) | HCC 18 | ~0.30–0.40 | Physician documentation of “polycythemia vera”; JAK2 mutation, EPO suppression as supportive evidence. Do NOT code from labs alone. |
| D75.81 (Myelofibrosis) | Myeloproliferative Disorders and Myelodysplastic Syndromes (Moderate/Severe) | HCC 18 | ~0.30–0.40 | Documented myelofibrosis — primary or secondary (post-PV/ET). Bone marrow biopsy evidence in record. |
| D61.01, D61.810, D61.818, D61.3, D61.89, D60.x, D64.0, D64.1, D59.x (acquired hemolytic, aplastic, sideroblastic) | Acquired Hemolytic, Aplastic, and Sideroblastic Anemias | HCC 109 | ~1.14 (community non-dual aged) | Very high RAF. Requires specific type of aplastic/hemolytic/sideroblastic anemia documented. Do NOT assign D61.9 (unspecified aplastic anemia) when a specific type is known — HCC 109 requires specificity. |
| D63.0 (anemia in neoplastic disease) | Maps with underlying neoplasm HCC | Per neoplasm HCC | Per neoplasm HCC | Underlying malignancy must be coded first; D63.0 itself does not carry independent HCC weight — the malignancy code drives RAF. |
| D63.1 (anemia in CKD) | Maps with underlying CKD HCC | Per CKD stage HCC | Per CKD HCC | CKD stage must be documented and coded (N18.1–N18.6). CKD stage drives HCC; D63.1 is additional context code. |
| D62, D50.0, D64.9, D63.8, D64.81 | No independent HCC v28 mapping | N/A | 0 | These common anemia codes do not generate risk adjustment scores in v28. Value is in accurate DRG grouping and CC/MCC capture for inpatient reimbursement rather than outpatient RAF. |
Aplastic anemia / pancytopenia specificity: HCC 109 (RAF ~1.14) requires specific documentation of the TYPE of aplastic or hemolytic anemia. When a patient has documented pancytopenia (low RBCs, WBCs, and platelets), a CDI query should distinguish: (1) Antineoplastic chemotherapy-induced pancytopenia (D61.810), (2) Other drug-induced pancytopenia (D61.811), (3) Other pancytopenia (D61.818), or (4) Aplastic anemia with specific etiology. D61.818 (Other pancytopenia) maps to HCC 109 — a major RAF capture opportunity for Medicare Advantage patients with documented pancytopenia from any cause. Per HealthCare Partners Risk-Adjusted Coding Guide.
15. CDI Query Templates
All query templates below are designed to be non-leading and multiple-choice, compliant with AHIMA/ACDIS 2019 Query Practice Guidelines. Queries must be placed in the medical record and documented in the attending physician’s response.
| Clinical Scenario | Query Wording (Non-Leading, Multiple Choice) |
|---|---|
| Post-surgical declining hemoglobin, transfusion ordered | Dear Dr. [Name], During this admission, the patient experienced an intraoperative/postoperative decline in hemoglobin from [X] to [Y] g/dL and received [N] units of packed red blood cells. For accurate clinical documentation and coding, could you please clarify the clinical significance and etiology of this hemoglobin decline? Please choose one or more: ☐ Acute blood loss anemia (D62) — due to surgical blood loss ☐ Iron deficiency anemia, chronic blood loss (D50.0) — pre-existing chronic condition ☐ Anemia unspecified (D64.9) — etiology unclear ☐ Clinically insignificant — not a reportable condition for this encounter ☐ Other: _____________ Signature/Date: __________ |
| Patient with cancer receiving chemotherapy, Hgb < 10 g/dL | Dear Dr. [Name], The patient has a documented malignancy ([Cancer type]) and is currently on antineoplastic therapy. Labs show hemoglobin of [X] g/dL. For documentation completeness, please clarify the etiology of this patient’s anemia: ☐ Anemia in neoplastic disease (D63.0) — anemia directly caused by the malignancy (e.g., bone marrow infiltration) ☐ Anemia due to antineoplastic chemotherapy (D64.81) — anemia caused by the chemotherapy regimen ☐ Iron deficiency anemia due to GI blood loss (D50.0 or D62) — related to GI bleeding/blood loss ☐ Anemia unspecified (D64.9) — etiology undetermined ☐ Other: _____________ Signature/Date: __________ |
| CKD patient receiving ESA (epoetin/darbepoetin) | Dear Dr. [Name], The patient has documented chronic kidney disease and is being treated with an erythropoiesis-stimulating agent. For accurate diagnosis coding, please confirm the clinical relationship: ☐ Anemia in chronic kidney disease (D63.1) — anemia is a direct consequence of CKD ☐ Anemia of chronic disease, other (D63.8) — anemia related to another chronic condition, not CKD ☐ Iron deficiency anemia (D50.x) — iron deficiency is the primary driver of anemia ☐ Anemia unspecified (D64.9) ☐ Other: _____________ Signature/Date: __________ |
| Elevated Hgb/Hct with splenomegaly, JAK2 positive | Dear Dr. [Name], The patient has a hemoglobin of [X] g/dL and hematocrit of [Y]%, along with splenomegaly documented on imaging. Laboratory testing shows a positive JAK2 V617F mutation. Please document your clinical diagnosis for this patient’s elevated red cell mass: ☐ Polycythemia vera (D45) — primary myeloproliferative neoplasm, JAK2-driven ☐ Secondary polycythemia (D75.1) — reactive erythrocytosis from [specify cause, e.g., hypoxia, EPO-producing tumor] ☐ Familial erythrocytosis (D75.0) — hereditary/congenital cause ☐ Elevated hemoglobin, under evaluation — workup ongoing ☐ Other: _____________ Signature/Date: __________ |
| Pancytopenia in patient on chemotherapy | Dear Dr. [Name], The patient’s laboratory values demonstrate pancytopenia (low RBC, WBC, and platelet counts) during the current admission. This was noted in the setting of recent antineoplastic chemotherapy. For documentation accuracy, please clarify: ☐ Antineoplastic chemotherapy-induced pancytopenia (D61.810) ☐ Other drug-induced pancytopenia (D61.811) — non-antineoplastic drug ☐ Other pancytopenia (D61.818) — non-drug-related cause ☐ Aplastic anemia (D61.x) — specify type: ___________ ☐ Not a reportable diagnosis for this encounter ☐ Other: _____________ Signature/Date: __________ |
16. Treatments (Clinical)
Anemia — Clinical Management Overview
Treatment of anemia is directed by etiology, severity, and patient clinical status, per UpToDate: Approach to the Adult Patient with Anemia.
- Acute hemorrhagic anemia (D62): Immediate hemostasis is the priority (surgical, endoscopic, interventional radiology, or medical). Volume resuscitation with crystalloids; PRBC transfusion for Hgb < 7–8 g/dL (or < 10 g/dL in cardiovascular disease). Massive transfusion protocol (MTP) for hemorrhagic shock. Factor replacement if coagulopathy identified. Monitor INR/PT (CPT 85610) for anticoagulant-related hemorrhage.
- Chronic blood loss anemia (D50.0): Identify and treat the source of chronic blood loss. Oral iron supplementation (ferrous sulfate 325 mg TID) for 3–6 months after source control. IV iron (J1439, J1750, J1437) if GI intolerance or malabsorption. Monitor ferritin, transferrin saturation, and CBC monthly during repletion.
- Anemia of CKD (D63.1): ESA therapy (epoetin alfa J0885, darbepoetin J0881) targeting Hgb 10–11.5 g/dL per KDIGO 2012 Anemia Guidelines. Concurrent IV iron supplementation to maintain transferrin saturation > 20% and ferritin > 100 ng/mL. ESAs are contraindicated in active malignancy in most settings. Dialysis patients are separately managed (J0886 epoetin for ESRD).
- Anemia in neoplastic disease (D63.0): Treat underlying malignancy. ESAs used cautiously in chemotherapy-associated anemia per FDA black box warning — risk of tumor progression and thromboembolism. Transfusion threshold generally Hgb < 7–8 g/dL. Iron supplementation as needed. Transfusions preferred over ESAs in patients with curative intent.
- Drug-induced anemia (D64.81): Discontinue or substitute the causative agent when clinically feasible. Supportive care; transfusion for severe anemia. Folic acid supplementation for methotrexate-induced folate deficiency anemia.
Polycythemia — Clinical Management
- Polycythemia vera (D45): Goal is hematocrit < 45% (males) and < 42% (females) per NCCN MPN Guidelines v2.2025. Therapeutic phlebotomy (CPT 36415) is first-line for all patients. Low-dose aspirin 81–100 mg daily for all PV patients without contraindications. High-risk patients (age > 60 or prior thrombosis): cytoreductive therapy with hydroxyurea (first-line) or interferon-alpha (preferred in younger patients, pregnant women, or hydroxyurea intolerance). Ruxolitinib (JAK1/2 inhibitor) for hydroxyurea-resistant/intolerant PV. Monitor for transformation to myelofibrosis or AML.
- Secondary polycythemia (D75.1): Treat the underlying cause (supplemental oxygen for COPD/OSA, CPAP for sleep apnea, nephrectomy/embolization for EPO-producing renal tumors). Phlebotomy used symptomatically to reduce hematocrit when > 54–55% per UpToDate: Erythrocytosis. Avoid over-treatment — secondary polycythemia is often compensatory.
- Neonatal polycythemia (P61.1): Partial exchange transfusion with normal saline to reduce hematocrit to < 60–65%; reserved for symptomatic infants or Hct > 65–70%. Supportive care including IV fluids.
MS-DRG Context
Per the FY2026 ICD-10-CM/PCS MS-DRG v43.1 Definitions Manual (CMS), anemias most commonly group to:
- DRG 811: Red Blood Cell Disorders with MCC — includes D62, D50.x, D63.x, D64.x as principal diagnoses with MCC
- DRG 812: Red Blood Cell Disorders without MCC
- DRG 808–810: Major Hematological and Immunological Diagnoses (aplastic anemias, acquired hemolytic anemias) with/without MCC/CC
D62 (acute posthemorrhagic anemia) is classified as an MCC when it appears as a secondary diagnosis, significantly impacting DRG assignment and reimbursement. Accurate documentation and coding of D62 vs. D64.9 can represent a DRG shift worth thousands of dollars per admission.
17. Patient Education / Summary
For Patients: Understanding Your Diagnosis
What is anemia? Anemia means your blood does not have enough healthy red blood cells to carry oxygen throughout your body. This can make you feel tired, weak, short of breath, or dizzy. There are many different types and causes of anemia — iron deficiency, blood loss, kidney disease, and cancer-related anemia are among the most common. Your doctor will identify the type and cause before recommending treatment.
Anemia from blood loss: If you lost blood suddenly (from surgery, injury, or GI bleeding), you may develop anemia quickly. Your doctors will stop the bleeding, give fluids, and may give you a blood transfusion. If you have had slow, ongoing blood loss (such as from stomach ulcers or heavy periods), you may develop iron deficiency anemia over time. Iron pills or IV iron can help rebuild your iron stores once the source of bleeding is found and treated.
Anemia from kidney disease: Your kidneys make a hormone called erythropoietin (EPO) that signals your bone marrow to make red blood cells. When kidneys are not working well, EPO production falls. Your doctor may prescribe an EPO injection (such as epoetin or darbepoetin) and/or IV iron to help treat this type of anemia.
What is polycythemia? Polycythemia means your blood has too many red blood cells, making it thicker than normal. This can increase your risk of blood clots, stroke, and heart attack. Polycythemia vera (PV) is a bone marrow disease caused by a gene mutation. Secondary polycythemia can be caused by low oxygen levels from lung disease, sleep apnea, or other conditions.
Living with polycythemia vera: PV is a manageable condition. Regular therapeutic phlebotomy (blood removal) helps keep your red blood cell levels in a safe range. Daily aspirin reduces clot risk. You will need ongoing monitoring by a hematologist. Report new symptoms such as severe headaches, vision changes, leg swelling, or chest pain immediately, as these may indicate a blood clot.
Key warning signs — call your doctor or go to the ER:
- Sudden severe shortness of breath, chest pain, or rapid heartbeat
- Black/tarry stools, blood in vomit, or heavy unexplained bleeding
- Dizziness, fainting, or sudden weakness
- Severe headache, vision changes, or one-sided weakness (possible stroke)
- Leg pain, swelling, or redness (possible DVT)
Understanding your treatment: Your care team will explain which type of anemia or polycythemia you have and the best treatment plan. Be sure to tell your doctor about all medications, supplements, and vitamins you take — some can affect blood counts. For anemia, it is important to follow up for repeat blood tests (CBC, iron studies) to monitor treatment response. For polycythemia vera, regular follow-up with a hematologist is essential for life-long management.
Before finalizing coding for anemia or polycythemia encounters, verify documentation includes:
- ✅ Type/etiology of anemia documented by provider (not just “anemia” or “low hemoglobin”)
- ✅ Acuity established: acute vs. chronic blood loss when applicable
- ✅ Causal relationship documented when coding D63.x (provider must state anemia is “due to” or “in the setting of” the underlying condition)
- ✅ Drug identified when coding D64.81 (adverse effect code required)
- ✅ CKD stage documented when coding D63.1 (N18.x must be assigned first)
- ✅ Polycythemia type specified: vera (D45) vs. secondary (D75.1) vs. familial (D75.0)
- ✅ Sequencing reviewed: underlying condition first when “Code first” instruction applies
- ✅ No simultaneous assignment of D62 and D50.0 (Excludes1)
- ✅ MS-DRG impact reviewed: D62 as secondary diagnosis = MCC; D64.9 = no CC/MCC impact
About this Guide
This Clinical Documentation Guide is published by CCO Academy and is intended for credentialed coding, CDI, and clinical documentation professionals. Content is updated for FY2026 ICD-10-CM (effective October 1, 2025). All code assignments should be verified against the official ICD-10-CM Tabular List, AHA Coding Clinic, and applicable payer-specific policies. This guide does not constitute legal, medical, or compliance advice.
Last reviewed: April 2026 · Next scheduled review: October 2026 (FY2027 update)
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