MLT 1304 Final Exam

• Discocyte


  Red blood cell (RBC) lacking nucleus and organelles, biconcave disc shape
• Red Blood Cell (RBC)

  • 120 day survival
  • 7-8 μm with average volume of 90 fL
  • Transports oxygen, removes carbon dioxide
  • Pliable membrane made of lipids and proteins allows it to sustain constant surface to volume ratio
• Assessment of Red Blood Cell Morphology

  1. Well stained smear with even distribution of RBC's is required

  2. Assessment of anisocytosis (size) or poikilocytosis (shape)

  3. Aniso is aided by RBC indices and RDW

  4. Assess 10 OIF

  5. Most labs use qualitative remarks (few/moderate) or quantitative (1+ -4+) to describe type of cell or variation from normal

  6. Don't use vague terms like "present"

  7. Very subjective

  8. Labs will have policies specifying how it will be done according to facility
• Grading Scale for RBC Morphology

  • Normal (5%)
  • Slight (5-10%)
  • 1+ (10-25%)
  • 2+ (25-50%)
  • 3+ (50-75%)
  • 4+ (>75%)
• Rouleaux


  Abnormal distribution of RBCs where they stack up like coins
• Who Has Rouleaux?


  • Hyperproteinemias
  • Multiple myeloma and Waldenstrom's Macroglobulinemia
  • Chronic inflammatory disorders and some lymphomas
• Microcytes


  RBCs less than 7 μm or MCV less than 80 fL, seen in microcytic anemias
• Macrocytes


  RBCs greater than 7 μm or MCV greater than 100 fL, seen in megaloblastic anemias
• Other Conditions Causing Macrocytosis

  • Liver disease
  • Hemoglobinopathies
  • Thalassemias
  • Anemia
• Hypochromia


  Decreased surface to volume ratio and decreased or absent central pallor
• Hyperchromia


  Decreased surface to volume ratio and decreased or absent central pallor, MCHC > 360
• Polychromasia


  Increased reticulocytes, immature RBCs with more RNA
• Target Cells (Codocytes)


  Appear as a result of increase in RBC surface membrane, excess membrane cholesterol/phospholipid with decreased cellular hemoglobin
• Spherocytes


  Reduced surface to volume ratio, no central pallor, most common RBC morphological disorder stemming from abnormality of membrane
• Stomatocytes


  Central pallor that is slit like or mouth like, thought to be result of membrane defect
• Ovalocytes and Elliptocytes


  Oval or elliptical shaped RBCs
• Sickle Cells (Drepanocytes)


  Crescent or sickle shaped with pointed projections at one or both ends, rigid and inflexible
• Irreversible vs Reversible Sickle Cells

  Cells that can't revert to discocyte upon oxygenation cause sickling events
• Fragmented cells (Schistocytes/Helmet)


  Split, cut or cloven RBCs resulting from trauma to membrane, seen in microangiopathic hemolytic anemia, DIC, heart valve surgery, etc.
• Helmet/Bite cells


  RBCs caught on fibrin strands, gets stuck and drapes over fibrin, makes a vacuole which resembles a blister or purse
• Echinocytes (Burr Cells)


  RBCs with spiny projections
• Acanthocytes (Thorn Cells, Spur Cells)


  RBCs with irregular spiny projections
• Teardrop Cells (Dacrocytes)


  RBCs with a teardrop shape, caused by inclusions that pinch the cell
• Howell Jolly Bodies


  Nuclear remnants containing DNA, seen in conditions with splenic dysfunction
• Basophilic Stippling


  RBCs containing ribosomes, result of altered hemoglobin biosynthesis
• Pappenheimer Bodies (Siderotic granules)


  Small, irregular, magenta inclusions seen in periphery of RBCs, presumptive evidence of iron
• Heinz Bodies


  Result of denatured or precipitated hemoglobin, cannot be visualized by Romanowsky stains
• Cabot Rings


  Rare inclusion bodies in RBCs
• Hemoglobin CC Crystals


  Hexagonal crystals formed by abnormal hemoglobin, seen in hemoglobin CC disease
• Hemoglobin SC Crystals


  Crystals formed by abnormal hemoglobin, seen in hemoglobin SC disease
• Protozoan Inclusions


  Parasites like Plasmodium and Babesia that can be seen inside RBCs
• Platelet Morphology


  • 2-4 μm, discoid shape, blue granules dispersed throughout light blue cytoplasm
• Toxic Granulation


  Medium to large granules evenly scattered in neutrophils, seen in severe bacterial infections, toxemia of pregnancy, vasculitis, chemotherapy
• Dohle Bodies


  Basophilic inclusions in neutrophils, indicate non-specific reactive changes
• Toxic Vacuolization


  Round clear unstained areas dispersed in neutrophils, indicates bacterial infection
• Shift to the Left


  Toxic changes plus leukocytosis and shift to the left, common in severe bacterial infections
• Leukemoid Reactions


  Peripheral neutrophilia that resembles chronic leukemia, WBC between 50-100
• Neutrophil Segmentation


  6 or more lobes=hypersegmentation (megaloblastic process), 2 lobes or less=hyposegmentation (Pelger-Huet anomaly)
• Leukocytosis Without Shift to Left

  • Exercise
  • Intense emotional stress
  • Anesthesia
  • Administration of epinephrine or glucocorticoids
• Discocyte


  Red blood cell (RBC) lacking nucleus and organelles