Classification of Anemia by Cause

Mechanism

Examples

Blood loss

Acute

Childbirth

Gastrointestinal (GI) bleeding

Injuries

Surgery

Chronic

Bladder tumors

Cancer or polyps in GI tract

Heavy menstrual bleeding

Kidney tumors

Ulcers in the stomach or small intestine

Deficient or ineffective erythropoiesis*

Microcytic

Anemia of chronic disease

Iron deficiency

Iron-transport deficiency (iron refractory iron deficiency anemia [IRIDA])

Iron utilization defect (inherited sideroblastic anemia)

Thalassemia

Normochromic-normocytic

Anemia of chronic disease

Kidney disease

Endocrine failure (thyroid, pituitary)

Myelodysplasia

Myelophthisis

Parvovirus B19 infection

Pure red blood cell aplasia

Undernutrition

Macrocytic

Alcohol use disorder

Folate deficiency

Liver disease

Malabsorption (eg, tropical sprue)

Myelodysplasia

Vitamin B12 deficiency

Excessive hemolysis due to extrinsically induced red blood cell abnormalities

Reticuloendothelial hyperactivity with splenomegaly

Hypersplenism

Immunologic abnormalities

Cold agglutinin disease

Drug-induced

Paroxysmal cold hemoglobinuria

Warm antibody hemolytic anemia

Infection

Clostridial infections

Ebstein Barr virus (EBV) infection

Malaria

Mechanical injury

Cardiac valvular disease

Foot strike hemolysis

Thrombotic microangiopathies (hemolytic uremic syndrome [HUS], atypical or complement-mediated HUS, and thrombotic thrombocytopenic purpura [TTP])

Drugs/toxins

Spider bites

Excessive hemolysis due to intrinsic red blood cell defects

Membrane alterations, acquired

Acquired stomatocytosis

Hypophosphatemia

Membrane alterations, congenital

Hereditary elliptocytosis

Hereditary spherocytosis

Hereditary stomatocytosis

Hereditary xerocytosis

Neuroacanthocytosis

Metabolic disorders (inherited enzyme deficiencies)

Glycolytic pathway defects (Embden-Meyerhof pathway defects)

Glucose-6-phosphate dehydrogenase (G6PD) deficiency

Hemoglobinopathies

Hemoglobin C disease

Hemoglobin E disease

Sickle cell disease (Hb SS disease, Hb S-C disease, Hb S–beta-thalassemia disease)

Thalassemias (beta, beta-delta, and alpha)

* Classified according to red blood cell indices.

In these topics