Leukopenia is a hematologic condition characterized by a total white blood cell (WBC) count below the lower limit of normal — typically defined as fewer than 4,000 cells/µL in adults — reflecting a reduction in one or more of the major leukocyte subtypes: neutrophils, lymphocytes, monocytes, eosinophils, or basophils. It is distinguished from neutropenia (a deficiency specifically of neutrophils, the most abundant WBC subtype and primary bacterial defense cell), lymphopenia (a deficiency specifically of lymphocytes, critical to adaptive immunity), and leukocytosis (the opposite state — an elevated WBC count), though neutropenia is the most clinically dangerous subtype and is the most common cause of leukopenia overall. The underlying physiological mechanism involves either decreased production of leukocytes in the bone marrow (e.g., due to marrow suppression from chemotherapy, radiation, or infiltrative disease), accelerated peripheral destruction (e.g., autoimmune leukopenia, hypersplenism), or abnormal redistribution of cells from the circulating to the marginating pool. Leukopenia may be physiological in certain populations (e.g., benign ethnic neutropenia in individuals of African descent) or pathological, with pathological causes including hematologic malignancies (leukemia, myelodysplastic syndrome), infections (HIV, viral syndromes), autoimmune diseases (systemic lupus erythematosus M32.9), and medication toxicity (chemotherapy agents, clozapine, carbimazole). In ICD-10-CM coding, leukopenia without further specification is captured under D72.819 (Decreased white blood cell count, unspecified), while neutropenia maps to the D70 category and lymphopenia to D72.810 — important distinctions that require specific documentation to code correctly. It is commonly confused with agranulocytosis, which is a severe, potentially life-threatening form of neutropenia (absolute neutrophil count <500/µL) and codes to the D70 family, not to D72.81x.
“white,” “clear,” “bright” — used in medical terminology to denote white blood cells or white-colored structures
-penia
Greek penia (PEE-nee-ah), from penēs (πένης), from penesthai (to be poor/needy)
“poverty,” “deficiency,” “abnormal reduction” — suffix denoting a shortage or insufficiency of a cellular element
The word entered English in the early 1900s as leukopenia (noun), formed directly from Greek roots as a 20th-century medical coinage following the development of differential blood counts. The combining root leuko- (“white”) connects Leukopenia to the entire leuko- root family: leukocyte (leuko- + -cyte → white cell), leukemia (leuko- + -emia → white blood condition), and leukoplakia (leuko- + plakia → white patch/lesion). The deficiency suffix-penia is one of the most productive suffixes in hematology and laboratory medicine, also appearing in neutropenia, thrombocytopenia, erythropenia, eosinopenia, and pancytopenia.
Hypoleukocytosis(clinical synonym; older term occasionally appearing in hematology literature; same coding as leukopenia — D72.819)
Low white blood cell count(lay term used in patient-facing documentation, discharge instructions, and informed consent)
Neutropenia(most common and clinically significant subtype — deficiency of neutrophils specifically; codes under D70 family, NOT D72.81; requires separate documentation of ANC)
Lymphopenia(deficiency of lymphocytes specifically; coded D72.810; commonly associated with HIV, immunosuppression, and viral infections)
Agranulocytosis(severe neutropenia — ANC <500/µL; coded under D70.9 or specific subtype; a hematologic emergency requiring immediate clinical action)
Autoimmune leukopenia(leukopenia caused by autoantibody-mediated WBC destruction; coded D70.8 if neutrophil-specific or D72.819 if broader; often seen in SLE)
Chemotherapy-induced leukopenia(drug-induced marrow suppression; requires an adverse effect code — T45.1X5A for initial encounter — as principal/first-listed with D70.1 for chemotherapy-induced neutropenia)
Pancytopenia(reduction of all three cell lines — RBCs, WBCs, and platelets — simultaneously; coded D61.818 other pancytopenia or D61.09 other constitutional aplastic anemia; more severe than leukopenia alone)
Febrile neutropenia(leukopenia + fever — a coding pair requiring both D70.9 or specific neutropenia code AND R50.81 fever associated with conditions classified elsewhere; clinically urgent — often triggers hospitalization)
Myelosuppression(broader term for bone marrow suppression causing leukopenia, thrombocytopenia, and/or anemia — often used in oncology context; not a standalone ICD-10 code; code the specific cytopenias)
🔗 RELATED TERMS
leukocytosis — the opposite of leukopenia; an abnormally elevated total WBC count (>11,000/µL); coded under D72.829 (unspecified) or specific subtype codes; commonly reactive to infection or inflammation
Neutropenia — the most common and clinically important subtype of leukopenia; defined as ANC <1,500/µL; codes independently under D70 family; primary risk factor for bacterial and fungal infections
Lymphopenia — deficiency of lymphocytes (<1,000/µL in adults); coded D72.810; hallmark of HIV/AIDS, immunosuppressive therapy, and some viral infections
Pancytopenia — simultaneous reduction of WBCs, RBCs, and platelets; most commonly caused by aplastic anemia, myelodysplastic syndrome, or marrow infiltration; coded D61.818 or by underlying cause
Thrombocytopenia — isolated platelet deficiency; frequently co-occurs with leukopenia in bone marrow failure states; coded under D69.3-D69.6 depending on etiology
Agranulocytosis — severe, life-threatening form of neutropenia; historically used synonymously with neutropenia; coded under D70.9 (unspecified) or specific etiologic subtype
Myelodysplastic syndrome (MDS) — clonal bone marrow disorder causing ineffective hematopoiesis and cytopenias including leukopenia; coded under D46 category; important underlying cause to code when documented
Aplastic anemia — bone marrow failure causing pancytopenia including leukopenia; coded D61.3 (idiopathic), D61.09 (other constitutional), D61.1 (drug-induced); must distinguish from MDS
Bone marrow suppression — mechanistic term for the failure of marrow to produce adequate blood cells; not a standalone ICD-10 code — code the resulting cytopenia(s) and the causative agent
Splenomegaly — enlarged spleen that sequesters and destroys circulating WBCs (hypersplenism), contributing to leukopenia; coded R16.1 (splenomegaly NOS) or by underlying cause
Systemic lupus erythematosus (SLE) — autoimmune disease frequently causing leukopenia via autoantibodies against WBCs; coded M32.9 or specific organ-involvement subtype; leukopenia is a diagnostic criterion for SLE
G-CSF (Granulocyte Colony-Stimulating Factor) — primary pharmacologic treatment for neutropenia/leukopenia (e.g., filgrastim, pegfilgrastim); stimulates bone marrow to produce neutrophils; administered in oncology and bone marrow failure settings
Complete blood count (CBC) — the primary diagnostic laboratory test for identifying leukopenia; coded 85027 (automated CBC) or 85025 (CBC with differential); must be accompanied by clinical documentation for diagnosis reporting
Subsequent hospital inpatient care, high complexity — use when leukopenic patient requires high MDM (e.g., febrile neutropenia with sepsis, new antibiotic regimen)
⚠️ Coding Note: Leukopenia is a symptom/lab finding-level code — D72.819 (decreased WBC count, unspecified) should only be sequenced as principal diagnosis when no more specific underlying condition has been identified; if the leukopenia is attributable to a confirmed cause (chemotherapy → D70.1, SLE → M32.9, MDS → D46.x, aplastic anemia → D61.x), code the underlying condition first and leukopenia as an additional diagnosis per ICD-10-CM sequencing guidelines. The single most important distinction on inpatient profee claims is neutropenia (D70.x) vs. leukopenia (D72.819) — these are NOT interchangeable; D72.819Excludes1 neutropenia (D70.-), meaning they cannot be coded together for the same WBC reduction event; if the physician documents “neutropenia,” code D70.x only. A critical undercoding alert: chemotherapy-induced neutropenia (D70.1) is routinely missed on oncology inpatient claims — documentation triggers include “ANC below 1,500,” “held chemo due to counts,” “nadir,” or “G-CSF administered” — query the attending if only “low WBC” or “myelosuppression” is documented without specifying neutropenia. For febrile neutropenia, always code both the neutropenia (e.g., D70.1) AND R50.81 together — failure to add R50.81 understates severity and impacts DRG assignment and CC/MCC capture. For bone marrow procedures, use 38222 when both biopsy and aspiration are performed at the same session — never report 38220 + 38221 together; add 88305 for the pathology interpretation of the core biopsy specimen and 85097 for the aspiration smear interpretation.
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