WBC

Overview of Hemoglobin and Hemolysis

  • Understanding whether a patient is truly anemic or if the values are affected by artifacts.
    • If hemoglobin is increased, it may be due to hemolysis, not due to more RBCs being produced by the cell.
    • Low hemoglobin can be misleading if there is an increased free hemoglobin in the plasma due to RBC lysis.

Hemolysis Considerations

  • Conditions to suspect actual hemolysis:
    • Visible signs of hemolysis in the plasma.
    • Abnormal values in hematology tests.
  • Key indicators when assessing hemolysis:
    • MCHC (Mean Corpuscular Hemoglobin Concentration)
    • Utilized to evaluate hemolysis based on hemoglobin concentration relative to red cell count.
    • Visual inspection for hemolyzed plasma is crucial.

Garlic and Onion Toxicosis in Animals

  • Association with Heinz bodies and hemolysis.
  • Clinical signs of garlic and onion toxicosis take time to develop, generally 2-3 days after ingestion:
    • Symptoms: lethargy, anorexia, tachypnea, tachycardia, weakness, exercise intolerance.
    • Importance of timing after toxin exposure when examining clinical signs and hematology results.
  • The presence of Heinz bodies indicates oxidative damage to RBCs, which may not be immediately visible in blood work.

Understanding Basic Hematology Terminology

  • Leukocytes (white blood cells): Indicators of health and disease; numbers fluctuate based on body status.
  • Leukogram: Comprehensive analysis of leukocyte count and morphology.
  • Key changes in leukogram to note:
    • Individual leukocyte changes and total count alterations.
    • Reference intervals for various species (dogs, cats, horses, etc.).

Neutrophils

  • Neutrophils are among the most significant and numerous leukocytes; their concentration can change rapidly due to infection or inflammation.
  • Important definitions:
    • Leukocytosis: Elevated white blood cell count.
    • Leukopenia: Decreased white blood cell count.

Neutrophil Production and Morphology

  • Neutrophil maturation cycle:
    • Takes roughly 7 days from myeloid stem cells to mature neutrophils in a healthy state.
    • Bone marrow's compartmentalization and storage pools for immediate release during infection or stress.
  • Normal neutrophil responses in blood work:
    • Neutrophilia typically indicates a physiologic reaction (stress, inflammation).
    • Should assess the immature versus mature neutrophils in circulation.

Left Shift Phenomenon

  • Left Shift: Increase in immature neutrophils (bands) in circulation, indicative of a response