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Book

Macrocytic Anemia

Robert B. Killeen  1 , Abdullah Adil  2
In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan.
.
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Book

Macrocytic Anemia

Robert B. Killeen et al.
Free Books & Documents

Excerpt

Macrocytic anemia refers to macrocytosis, a mean corpuscular volume (MCV) >100 fL, in the setting of anemia. Generally, the following thresholds define anemia:

  1. For nonpregnant females: hemoglobin <12 g/dL or hematocrit (Hct) <36%

  2. For pregnant females: hemoglobin <11 g/dL

  3. For males: hemoglobin <13 g/dL or Hct <41%

Macrocytic anemia is divided into 2 forms: megaloblastic (hypersegmented neutrophils) and nonmegaloblastic. The megaloblastic form is due to impaired DNA synthesis from folate or vitamin B12 deficiencies, while the nonmegaloblastic moiety occurs from multiple mechanisms.

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Conflict of interest statement

Disclosure: Robert Killeen declares no relevant financial relationships with ineligible companies.

Disclosure: Abdullah Adil declares no relevant financial relationships with ineligible companies.

References

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    1. Válka J, Čermák J. [Differential diagnosis of anemia]. Vnitr Lek. 2018 Summer;64(5):468-475. - PubMed
    1. Wolffenbuttel BHR, McCaddon A, Ahmadi KR, Green R. A Brief Overview of the Diagnosis and Treatment of Cobalamin (B12) Deficiency. Food Nutr Bull. 2024 Jun;45(1_suppl):S40-S49. - PubMed
    1. Baek IW, Park KS, Kim KJ. An erythrocyte macrocytosis by methotrexate is associated with early initiation of biologic or targeted synthetic agents in patients with rheumatoid arthritis. J Rheum Dis. 2025 Jan 01;32(1):30-37. - PMC - PubMed
    1. Cakmakli HF, Torres RJ, Menendez A, Yalcin-Cakmakli G, Porter CC, Puig JG, Jinnah HA. Macrocytic anemia in Lesch-Nyhan disease and its variants. Genet Med. 2019 Feb;21(2):353-360. - PMC - PubMed

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