D61.818: Other pancytopenia

The ICD-10-CM code for pancytopenia when all three blood cell lines are reduced and the cause is neither antineoplastic chemotherapy nor another drug.

Billable

FY2027

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At a glance

Code Family

D61: Other aplastic anemias and other bone marrow failure syndromes.

DRG Grouping

MS-DRG 808, 809 or 810 in MDC 16 under the FY2027 MS-DRG v44 grouper.

HCC Mapping (v28)

HCC 109, Acquired Hemolytic, Aplastic, and Sideroblastic Anemias.

Condition

Pancytopenia

Family Specificity

Subcategory D61.81- divides pancytopenia by cause across three billable codes, with D61.818 as the residual for pancytopenia that is neither chemotherapy induced nor otherwise drug induced.

Effective Date

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

Which D61 code do I assign?

Category D61 splits first on whether the record documents aplastic anemia or pancytopenia. Within subcategory D61.81- the split is on cause alone: D61.818 is the residual for pancytopenia that is neither antineoplastic chemotherapy induced nor otherwise drug induced.

When documentation says…

Code

Pancytopenia after cycle 3 of chemotherapy

D61.810

Pancytopenia the provider attributes to antineoplastic chemotherapy. The note must name chemotherapy as the cause. The treated neoplasm and the agent should both appear in the record.

Drug-induced pancytopenia secondary to linezolid

D61.811

Pancytopenia the provider attributes to a drug other than antineoplastic chemotherapy. The note must name the drug, or state that the pancytopenia is drug induced.

Pancytopenia, etiology under investigation

D61.818

Pancytopenia with no drug cause documented. This is the residual code. The FY2027 Alphabetic Index sends the unqualified term Pancytopenia (acquired) to D61.818.

Pancytopenia due to acute myeloid leukemia

D61.818

Pancytopenia caused by a malignancy that the Excludes1 notes at the D61.81- level do not name. Report the leukemia code as well. AHA Coding Clinic, First Quarter 2023, page 23, addressed this pairing.

Aplastic anemia

D61.9

Marrow failure documented as aplastic anemia. An Excludes1 note at the D61.81- level bars reporting pancytopenia with aplastic anemia. Assign the aplastic anemia code alone.

Pancytopenia from marrow infiltration by metastatic carcinoma

D61.82

Myelophthisis, which covers pancytopenia with bone marrow infiltration and leukoerythroblastic anemia. An Excludes1 note at the D61.81- level bars D61.818 here. Code also the underlying disorder.

Congenital pancytopenia

D61.09

Pancytopenia present from birth, including pancytopenia with malformations. The FY2027 Alphabetic Index routes both terms to D61.09. Fanconi pancytopenia routes instead to D61.03.

Tabular notes

EXCLUDES1

Subcategory D61.81- carries Excludes1 notes that bar any D61.81- code, including D61.818, when the pancytopenia is documented as due to or with the following: aplastic anemia (D61.9), bone marrow infiltration (D61.82), congenital (pure) red cell aplasia (D61.01), hairy cell leukemia (C91.4-), human immunodeficiency virus disease (B20.-), leukoerythroblastic anemia (D61.82), myeloproliferative disease (D47.1). Excludes1 means the two are not reported together for the same condition. Assign the excluded code in place of D61.818. For pancytopenia with aplastic anemia, the aplastic anemia code stands alone. Congenital pancytopenia is indexed to D61.09 rather than to any D61.81- code.

EXCLUDES2

Category D61 carries an Excludes2 note for neutropenia (the D70 codes). Subcategory D61.81- carries an Excludes2 note for pancytopenia due to or with myelodysplastic syndromes (the D46 codes). Excludes2 means the patient may have both conditions. Report D61.818 and the myelodysplastic syndrome code together when both are documented. The two sibling codes add their own Excludes2 notes. D61.810 excludes aplastic anemia due to antineoplastic chemotherapy (D61.1). D61.811 excludes aplastic anemia due to drugs (D61.1).

FY2027: EFFECTIVE 1 OCTOBER 2026

The FY2027 codes and tabular addenda make no addition, deletion or revision in category D61. The FY2027 chapter 3 changes fall at categories D68 and D69 and at block D80-D89. D61.818 is unchanged in the FY2027 update. The tabular carries no Use additional code, Code also or Code first instruction at D61.818 or at any of its parent levels.

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+)

HCC 109: Acquired Hemolytic, Aplastic, and Sideroblastic Anemias.

D61.810 and D61.811 map to no HCC under v28.

CMS phased v28 in over three payment years. It carries the full risk score for payment year 2026, per the CY2024 Rate Announcement.

For Medicare Advantage risk adjustment, the pancytopenia must be documented as actively addressed during the calendar year. The code must appear on a dated face to face encounter note rather than only on a problem list.

MS-DRG v44 (FY2027)

MS-DRG 808: Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with MCC.

MS-DRG 809: Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders with CC.

MS-DRG 810: Major Hematological and Immunological Diagnoses Except Sickle Cell Crisis and Coagulation Disorders without CC/MCC.

D61.818 as principal diagnosis groups to MDC 16 and to MS-DRG 808, 809 or 810 under the FY2027 MS-DRG v44 grouper.

Medicare and commercial payers

There is no National Coverage Determination specific to pancytopenia diagnosis coding.

D61.818 carries no billing restriction unique to the diagnosis code.

These rules apply to Medicare Fee for Service and to Medicare Advantage plans using CMS-HCC v28 for payment year 2026.

WHERE SPECIFICITY IS LOST

Assigning D61.818 when the note documents chemotherapy as the cause adds HCC 109 to the risk score. D61.810 is the correct code in that scenario and maps to no v28 HCC.

Assigning D61.818 alongside a documented aplastic anemia diagnosis violates the Excludes1 note carried at the D61.81- level.

Reporting anemia, thrombocytopenia and a decreased white blood cell count as three separate codes when the provider documented pancytopenia loses the D61.818 mapping to HCC 109.

A note that records three low counts without a provider statement of pancytopenia supports only the individual cytopenia codes. Query for a unifying diagnosis.

SEVERITY DESIGNATION (MS-DRG V44.0)

D61.818 is a CC. It appears in Appendix G, diagnoses defined as complications or comorbidities, in the ICD-10 MS-DRG Definitions Manual Version 44.0. As a secondary diagnosis it can move a case to a with-CC tier where the DRG pair offers one.

Documentation checklist to support D61.818

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

A provider statement of pancytopenia, or documentation that the red cell, white cell and platelet lines are all reduced.

Counts for all three lineages drawn in the same period: hemoglobin or hematocrit, white blood cell count or absolute neutrophil count, and platelet count.

A cause statement, or an explicit statement that the cause has not been established.

Documentation ruling out antineoplastic chemotherapy and any other drug as the cause. A documented drug cause directs the encounter to the D61.810 or D61.811 codes.

The absence of a documented aplastic anemia, myelophthisis, hairy cell leukemia, myeloproliferative disease or HIV disease diagnosis. Each of those is an Excludes1 condition at the D61.81- level.

The underlying disease when one is documented, such as acute myeloid leukemia or systemic lupus erythematosus.

The workup and the treatment: peripheral smear, bone marrow biopsy, transfusion, growth factor support or withdrawal of a suspected drug.

Evidence of active clinical management during the calendar year, to support annual recapture under CMS-HCC v28.

For outpatient encounters, a confirmed diagnosis only. Suspected or probable pancytopenia is not coded in the outpatient setting.

FAQ

Is D61.818 a billable code?

Yes. D61.818 is a complete six character code and is valid for submission. The parent D61.81, Pancytopenia, is a subcategory rather than a code. A claim carrying D61.81 alone rejects as an invalid diagnosis code.

When do I use D61.810 or D61.811 instead of D61.818?

Use D61.810 when the provider attributes the pancytopenia to antineoplastic chemotherapy. Use D61.811 when the provider attributes it to any other drug. D61.818 is the residual and is correct only when neither cause is documented. The tabular carries no Use additional code instruction at D61.810. The adverse effect code for the drug, from the T45.1X5- codes, follows from Section I.C.19.e of the FY2027 Official Guidelines rather than from a tabular note. The tabular does carry that instruction one category away, at D70.1, agranulocytosis secondary to cancer chemotherapy: Code also underlying neoplasm, and Use additional code for adverse effect, if applicable, to identify drug (T45.1X5).

Does D61.818 map to an HCC under CMS-HCC v28?

Yes. D61.818 maps to HCC 109, Acquired Hemolytic, Aplastic, and Sideroblastic Anemias, in the CMS-HCC v28 model used for payment year 2026. D61.810 and D61.811 map to no v28 HCC.

Can I report D61.818 with aplastic anemia?

No. An Excludes1 note at the D61.81- level lists pancytopenia due to or with aplastic anemia and points to D61.9. Excludes1 means the two are not reported together for the same condition. Assign the aplastic anemia code alone.

Two of the three cell lines are low. Is that pancytopenia?

No. Pancytopenia requires all three lines to be reduced. StatPearls gives the usual thresholds as hemoglobin below 12 g/dL in women and below 13 g/dL in men, platelets below 150,000 per microliter, and leukocytes below 4,000 per microliter or an absolute neutrophil count below 1,800 per microliter. StatPearls notes that the thresholds vary with age, sex, race and clinical context. ICD-10-CM has no code for a two lineage cytopenia. Code each documented cytopenia separately: anemia (D64.9, or a specific code such as D63.8 when it is anemia in a chronic disease classified elsewhere), thrombocytopenia (D69.6), and neutropenia (D70.-) or a decreased white blood cell count (D72.819). Counts in the other direction sit in the companion subcategory D72.82-, elevated white blood cell count, which includes bandemia (D72.825).

When is D61.818 the principal diagnosis?

D61.818 is the principal diagnosis when the pancytopenia is the focus of the admission and the treatment. The guideline on anemia associated with malignancy, Section I.C.2.c.1, does not extend to pancytopenia. AHA Coding Clinic, First Quarter 2023, page 23, addressed pancytopenia due to acute myeloid leukemia and confirmed that D61.818 is reported with the leukemia code. AHA Coding Clinic, Third Quarter 2022, page 22, addressed neutropenic fever with pancytopenia due to chemotherapy.

Does D61.818 work the same way on outpatient claims?

The code is identical. The documentation bar differs. Outpatient coding requires a confirmed diagnosis. Probable or suspected pancytopenia is not coded in the outpatient setting. On the inpatient side, a diagnosis documented as uncertain at discharge may be coded as confirmed under the UHDDS rules. As principal diagnosis on an inpatient claim, D61.818 groups to MS-DRG 808, 809 or 810 in MDC 16 under the FY2027 MS-DRG v44 grouper.

What changed for D61.818 in FY2027?

D61.818 is unchanged in the FY2027 update. The FY2027 update, effective 1 October 2026, makes no addition, deletion or revision in category D61.

Related codes

Codes in the same family as D61.818. Only codes with a published page render as links.

Sibling codes in the D61 family

D61.01: Constitutional (pure) red blood cell aplasia.
D61.02: Shwachman-Diamond syndrome.
D61.03: Fanconi anemia.
D61.09: Other constitutional aplastic anemia.
D61.1: Drug-induced aplastic anemia.
D61.2: Aplastic anemia due to other external agents.
D61.3: Idiopathic aplastic anemia.
D61.810: Antineoplastic chemotherapy induced pancytopenia.
D61.811: Other drug-induced pancytopenia.
D61.82: Myelophthisis.
D61.89: Other specified aplastic anemias and other bone marrow failure syndromes.
D61.9: Aplastic anemia, unspecified.

Additional codes to consider

Codes outside the D61 family considered alongside D61.818.

Companion: code alongside when documented

D46.0–D46.9: Myelodysplastic syndromes, reportable with D61.818 under the Excludes2 note at D61.81.

Consider instead

D61.810: Antineoplastic chemotherapy induced pancytopenia, where chemotherapy is the documented cause.
D61.811: Other drug-induced pancytopenia, where a non-chemotherapy drug is the documented cause.
D61.9: Aplastic anemia, unspecified, an Excludes1 condition at the D61.81- level.
D61.82: Myelophthisis, for pancytopenia with bone marrow infiltration or leukoerythroblastic anemia.
D61.09: Other constitutional aplastic anemia, the index destination for congenital pancytopenia.
D64.9: Anemia, unspecified, where only the red cell line is documented as reduced.
D63.8: Anemia in other chronic diseases classified elsewhere.
D69.6: Thrombocytopenia, unspecified.
D70.9: Neutropenia, unspecified.
D72.819: Decreased white blood cell count, 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