Red Blood Cell

Aka: Red Blood Cell, Red Blood Cell Count, Erythrocyte Count, RBC Count, Erythropoiesis, Proerythroblast, Polychromatophilic erythroblast, Orthochromatic erythroblast, Reticulocyte

1. See Also
   1. Erythrocyte Morphology
   2. Anemia
2. Physiology: Erythropoiesis (mature red cell development)
   1. See Bone Marrow (Erythroblast)
   2. Images
      1. 
   3. Stimulation of RBC production
      1. Chronic Hypoxia (e.g. COPD, living at high altitude) stimulates renal erythropoetin release
      2. Erythropoetin stimulates RBC production in marrow
   4. Development in Marrow
      1. Proerythroblast is RBC stem cell in marrow (0.5 days)
      2. Basophilic Erythroblast (0.8 days)
         1. Nucleus shrinks, cytoplasm darkens with ribosomes
      3. Polychromatophilic erythroblast (1.3 days)
         1. Cell produces Hemoglobin
         2. Stains with basic and eosin stains
      4. Orthochromatic erythroblast (2.0 days)
         1. Cell appears more Eosinophilic
   5. Reticulocyte: Transition to Circulation
      1. Orthochromatic erythroblast sheds nucleus
      2. Marrow Reticulocyte spends 1.7 days in marrow
      3. Blood Reticulocyte spends 1.3 days in circulation
   6. Red Blood Cells in Circulation
      1. Mature Red Blood Cell (120 day life-span)
3. Findings: Normal Values (in 10^6/ul or 10^12/L) per age
   1. Age <1 month: 3.6 to 6.6
   2. Age 1-6 months: 2.7 to 5.4
   3. Age 0.5 - 6 years: 3.7 to 5.3
   4. Age 6-12 years: 4.0 to 5.2
   5. Female
      1. Age 12-18 years: 4.1 to 5.1
      2. Age >18 years: 3.8 to 5.2
   6. Male
      1. Age 12-18 years: 4.5 to 5.3
      2. Age >18 years: 4.4 to 5.9
4. Findings: Increased Red Blood Cell Count
   1. Polycythemia Vera
   2. Tobacco Abuse
   3. Living at High altitude
   4. Renal Cell Carcinoma
   5. Cardiovascular disease
   6. Stress
   7. Dehydration
   8. Thalassemia Trait
5. Findings: Decreased Red Blood Cell Count
   1. See Anemia
   2. Microcytic Anemia
      1. Iron Deficiency Anemia (most common)
      2. Thalassemia
      3. Lead Poisoning
      4. Anemia of Chronic Disease
      5. Sideroblastic Anemia
   3. Macrocytic Anemia
      1. Vitamin B12 Deficiency (Pernicious Anemia, most common)
         1. Atrophic Gastritis (loss of parietal cell produced intrinsic factor)
         2. Nitrous Oxide Abuse
      2. Folate Deficiency (often Alcohol related)
         1. See Medications Affecting Folate Metabolism
      3. Other causes (e.g. Myelodysplastic Syndrome)
   4. Hemoglobinopathy
      1. Sickle Cell Anemia
      2. Thalassemia
   5. Red Blood Cell Membrane defects
      1. Hereditary Spherocytosis
      2. Hereditary elliptocytosis
      3. Paroxysmal Nocturnal Hemoglobinuria
   6. Hemolytic Anemia
      1. See Hemolytic Anemia Causes
      2. See Drug-Induced Hemolytic Anemia
      3. See Autoimmune Hemolytic Anemia
      4. See Microangiopathic Hemolytic Anemia
      5. Infection (e.g. Epstein Barr Virus, Cytomegalovirus, Mycoplasma pneumonia)
      6. G6PD Deficiency
   7. Other Causes
      1. Acute Hemorrhage
      2. Marrow failure (Aplastic Anemia)
      3. Chronic Renal Failure (erythropoetin loss)