Introduction

• What is the average volume of blood in a human body?

  5 liters
• What are the primary functions of blood?

  Blood transports oxygen, clears carbon dioxide, transports nutrients, and moves wastes to organs.
• What is the liquid portion of blood called?

  Plasma
• What are the three categories of blood cells?

  Red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs).
• What is hematology?

  Hematology is the study of blood cells.
• Why do physicians rely on hematology laboratory test results?

  To select and monitor therapy for blood disorders.
• Who first described "worms" in the blood?

  Athanasius Kircher
• What did Anton van Leeuwenhoek describe in 1674?

  Red blood cells (RBCs)
• What significant development did James Homer Wright contribute in 1902?

  The development of the Wright stain for blood film examination.
• What is the scientific term for cell appearance in hematology?

  Morphology
• What is the shape and characteristic of red blood cells (RBCs)?

  RBCs are anucleate, biconcave, discoid cells.
• What protein do RBCs contain that is essential for gas transport?

  Hemoglobin
• What is the average diameter of red blood cells?

  7 to 8 µm
• What does hematocrit measure?

  The ratio of the volume of packed RBCs to the volume of whole blood.
• What is another name for hematocrit?

  Packed cell volume (PCV)
• What is the normal hematocrit ratio?

  It approaches 50%.
• What is the buffy coat in a hematocrit measurement?

  The light-colored layer between RBCs and plasma containing WBCs and platelets.
• What are the RBC indices that can be computed from RBC count, HGB, and HCT?

  Mean cell volume (MCV), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC).
• In what units is mean cell volume (MCV) recorded?

  Femtoliters (fL)
• What does mean cell hemoglobin concentration (MCHC) reflect?

  RBC staining intensity and amount of central pallor.
• What does mean cell hemoglobin (MCH) express?

  The mass of hemoglobin per cell in picograms (pg).
• What does RBC distribution width (RDW) indicate?

  The degree of variation in RBC volume.
• What is anisocytosis?

  Variation in RBC diameter visible on a Wright-stained blood film.
• How is the RBC count reported?

  In cells per microliter (µL), milliliter (mL), or liter (L).
• What was the first electronic counter used for RBC counting?

  The Coulter counter.
• What is the significance of reticulocytes in a blood film?

  They indicate the ability of the bone marrow to increase RBC production.
• What percentage of RBCs are reticulocytes in a normal blood film?


  0.5% to 2.5%
• What are reticulocytes stained with to visualize RNA?

  Methylene blue dyes.
• What is leukopenia?

  A decreased white blood cell count.
• What is leukocytosis?

  An increased white blood cell count.
• What is the role of white blood cells (WBCs)?

  To protect the host from infection and injury.
• How are WBCs typically counted?

  Using a microscope and hemacytometer with a dilution of 1:20.
• What happens to RBCs during WBC counting?

  RBCs are lysed or ruptured by a dilute acid solution.
• What is the significance of differentiating WBC types?

  It provides important diagnostic information about infections and diseases.
• What is leukemia?

  An uncontrolled proliferation of malignant WBCs.
• What are the two main types of leukemia?

  Chronic and acute leukemia.
• What is the role of platelets in the blood?

  To maintain blood vessel integrity and initiate vessel wall repairs.
• What is the diameter range of platelets?

  2 to 4 µm
• What is hemostasis?

  A series of mechanisms that seal wounds and maintain vascular patency.
• Why is it important to test specimens within the appropriate time frame?

  To ensure accurate analysis.