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Normal slight variation from normal red cell ... Hypochromia (correlate with MCHC) 1 area of central pallor is of cell diameter ... – PowerPoint PPT presentation

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Title: MLAB%201315-%20Hematology%20Fall%202007%20Keri%20Brophy-Martinez

MLAB 1315- HematologyFall 2007Keri
  • Unit 8 Morphological Changes Associated with

  • Evaluating and reporting anisocytosis (size) and
    poikilocytosis (shape)
  • RDW (red cell distribution width) is a measure
    expressed in percent of the variation in the red
    cell volume distribution.
  • Normal range 11.5-14.0
  • Grading scale
  • Normal slight variation from normal red cell
  • Slight 5-10 of cells vary in size or shape from
    normal red cell
  • 1 10-25 of cells vary in size or shape from
    normal red cell (Few)
  • 2 25-50 of cells vary in size or shape from
    normal red cell (Moderate)
  • 3 50-75 of cells vary in size or shape from
    normal red cell (Many)
  • 4 gt75 of cells vary in size or shape from
    normal red cell (Marked)

  • Size variations (correlate with MCV and RDW)
  • Causes of macrocytes
  • Caused by impaired DNA synthesis which leads to
    decreased number of cell divisions resulting in a
    larger red cell
  • Accelerated erythropoiesis which results in
    increased reticulocytes (retics are larger than
    mature red cells).
  • Causes of microcytes
  • Impaired hemoglobin synthesis which may be caused
    by iron problems
  • Decreased or defective globin synthesis

  • Stain variations
  • Hypochromia (correlate with MCHC)
  • 1 area of central pallor is ½ of cell diameter
  • 2 area of central pallor is of cell diameter
  • 3 area of central pallor is ¾ of cell diameter
  • 4 thin rim of hemoglobin
  • Polychromasia
  • Describes the blue-gray color of immature RBCs
    which have left the bone marrow prematurely.
  • These RBCs are larger than normal.
  • .he blue-gray color is due to residual RNA. When
    stained with a supravital stain such as methylene
    blue, they are called reticulocytes

  • Shape variations
  • Target cell (codocyte)
  • RBCs have a centrally stained area and resemble
    a shooting target.
  • Caused by excess membrane cholesterol or
    decreased hemoglobin content.
  • Seen in liver disease, hemoglobinopathies, iron
    deficiency anemia, post-splenectomy. Can also be
  • Spherocyte
  • Appear as small red cells with no central pallor
    they have the lowest surface area-volume ratio
    shape change is irreversible.
  • Caused by loss of membrane due to aging, antibody
    coating or genetic defect
  • Seen in autoimmune hemolytic anemia, transfusion
    reaction, hereditary spherocytic anemia.

  • Ovalocyte/Elliptocyte
  • Oval or cigar shaped red cells. May be
    normochromic or hypochromic, normocytic or
  • Exact mechanism for deformity is not well
  • Ovalocytes seen in myelodysplastic syndrome,
    thalassemia, pernicious anemia, B12 or folate
  • Elliptocyes seen in iron deficiency anemia,
    hereditary elliptocytosis, idiopathic
  • Stomatocyte
  • Normal size red cell with slitlike area of
    central pallor resembling a mouth.
  • Exact mechanism for abnormality not well defined.
    Usually artifactual
  • Seen in hereditary spherocytosis, hereditary
    stomatocytosis, acute alcoholism, Rh null

  • Sickle Cell (drepanocyte)
  • Red cell is in the shape of a sickle or crescent.
  • Caused by hemoglobin S polymerization into rigid
    inflexible cells with at least one pointed
    projection. Polymerization occurs in lowered
    oxygen level or decreased pH.
  • Seen in hereditary condition called sickle cell
    disease. Can be homozygous or heterozygous.
    Also seen in hereditary Hemoglobin C disease or
    combination of both.
  • Acanthocyte
  • Red cell of normal or slightly small size with
    3-8 thorny, spine-like projections that are
    irregularly spaced around the cell. The
    projections may vary in length.
  • Exact mechanism is unknown, but it is known that
    they have excess cholesterol and increased
    surface membrane.
  • Seen in congenital abetalipoproteinemia, alcohol
    intoxication, severe hepatic disease and

  • Fragmented red cells (Schistocytes, Burr cells,
    Helmet cells)
  • Schistocytes
  • Red cells appear as fragment of irregular size
    and shape.
  • Caused by loss of membrane by mechanical means.
  • Seen in patient with prosthetic heart valves,
    clostridial infections, microangiopathic
    hemolytic anemia, hemolytic uremic syndrome
    (HUS), thrombotic thrombocytopenia purpura (TTP),
    disseminated intravascular coagulation (DIC)
  • Helmet cells (also called bite cells)
  • Red cells resemble an army helmet with short
  • Caused by splenic pitting.
  • Seen in G6PD deficiency, pulmonary emboli and

  • Burr cells (echinocytes)
  • Red cells have regular sharp projections around
    the membrane.
  • Caused by various factors such as dehydration or
    a change in the tonicity of the intravascular
    fluid. Also can be artifactual.
  • Seen in renal disease, liver disease and burn

  • Variations in red cell distribution
  • Agglutination
  • Red cells clump together when cooled to room
    temperature. Saline will not disperse the
    clumps, but warming usually will.
  • Caused by red cell antibodies
  • Seen in cold antibody syndromes, paroxysmal cold
  • Rouleaux
  • Red cells are arranged in groups resembling
    stacks of coins. Saline will disperse the
  • Caused by elevated globulins or fibrinogen in the
  • Seen in multiple myeloma and Waldenstromss

  • Red cell inclusions
  • Howell-Jolly bodies
  • Single round, solid-staining purple dot composed
    of DNA located on the periphery of the RBC.
  • Caused by accelerated or ineffective
    erythropoiesis in which chromosome fragments are
    left in the cytoplasm.
  • Seen following splenectomy and in thalassemias,
    hemolytic anemias and megaloblastic anemia.
  • Basophilic stippling
  • Tiny, round, solid-staining blue granules
    composed of RNA. Can be diffuse, coarse or
  • Usually artifactual caused by precipitation of
    RNA during staining of the smear.
  • Seen defective or accelerated heme synthesis,
    lead poisoning and thalassemias.

  • Pappenheimer bodies (Siderotic granules in
    Prussian blue stain)
  • Purplish irregular aggregates of granules
    composed of ferric(Fe3) iron.
  • Caused by excess available iron throughout the
  • Seen in sideroblastic anemia, alcoholism,
    thalassemia, asplenism.
  • Heinz Bodies
  • May not be seen on Wrights stain. When stained
    with a supravital stain such as crystal violet or
    brillian cresyl blue, they appear as large blue
    inclusions that are rigid and distort the cell
  • Cause by denatured or precipitated hemoglobin.
  • Seen in alpha thalassemia, G6PD deficiency and
    unstable hemoglobin syndromes.

  • Cabot ring
  • Purplish ring-shaped, figure-eight, or
    loop-shaped structures composed of nuclear
    membrane remnants. Rarely seen.
  • Exact mechanism unkown
  • Seen in pernicious anemia, lead poisoning,
    homozygous thalassemia and post-splenectomy.