MCV

James Cima CBC/Differential

MCV MCH RED BLOOD CELL INDICES

  1. MCV- MEAN CORPUSCULAR VOLUME-refers to the size of the RBC and is classified as normal (normocytic), <82um3 (microcytic) and >100um3 (macrocytic).

MCV= HCT(%) x 10

RBC (10 to the 12/L)

Microcytic anemias (MCV 50-82) caused by:

  1. Disorders of iron metabolism such as iron deficiency from malabsorption, dietary inadequacy, increased iron loss or iron requirements due to chronic disease
  2. Disorders of porphyrin and heme synthesis such as sideroblastic anemias and globin synthesis (thalassemias and hemoglobinopathies).

Normocytic normochromic anemias (MCV 82-98 fL)

  1. Marrow hypoplasia such as aplastic anemia
  2. Marrow infiltration by malignant cells
  3. Decreased erythropoietin production from endocrine, renal, liver disease and malnutrition.

Macrocytic anemias (MCV 100-150 fL) are caused by:

  1. B12 (cobalamin) deficiency due to:
  • A lack of animal products (vegetarians)
  • Impaired absorption of intrinsic factor leading to pernicious anemia due to a destruction of gastric mucosa, ileitis, sprue and celiac disease. Infiltrative intestinal diseases such as lymphoma.
  • Increased requirements such as pregnancy, hyperthyroidism, pancreatic disease and neoplasms.
  • Enzyme deficiencies (cobalamin binding protein)
  • Parasites
  1. Folate deficiency due to:
  • Decreased intake due to lack of vegetables or from alcoholism
  • Impaired absorption due to steatorrhea, sprue, celiac disease and intrinsic intestinal disease
  • Increased requirements from pregnancy, hypothyroidism, hematopoiesis, neoplastic disease, exfoliative skin diseases.
  • Enzyme deficiencies.
  1. MCH- MEAN CORPUSCULAR HEMOGLOBIN is the measurement of the average weight of Hb per RBC

MCH  = Hb(g/dL) x 10

(pg/cell RBC (10 to the 12th/L

An increase in MCH is associated with infections, macrocytic anemia, and newborns

A decrease is associated with toxic reactions, microcytic anemia, hyperlipidemia, high WBC counts >50,000 mm3 and high heparin can falsely elevate MCH levels.

  1. MCHC- MEAN CORPUSCULAR HEMOGLOBIN CONCENTRATION measures the average concentration of Hb in the RBC’s where the MCHC cannot be more than 37 g/dL per RBC

MCHC (g/dL)=Hb (g/dl) x 100

Hct (%)

An increased MCHC is found in:

  1. Newborns and infants
  2. A decrease in MCHC is found in:
  3. Iron deficiency
  4. Microcytic anemias
  5. Chronic blood loss
  6. Some thalassemias