Hematology

• Hematology

  • Study of the formed (cellular) elements of the blood.
  • Hematology Section
  • cellular elements, red blood cells (RBCs), white blood cells (WBCs), and platelets (Plts) are enumerated and classified in all body fluids and in the bone marrow.
  • the MLT or MLS can detect disorders such as leukemia, anemia, other blood diseases, and infection and monitor their treatment
• Whole Blood

  • most common body fluid analyzed in the hematology section
  • a mixture of cells and plasma
  • obtained by using a collection tube with an anticoagulant to prevent clotting of the sample.
• • Blood 
  • the body's main fluid for transporting nutrients, waste products, gasses, and hormones through the circulatory system
  • Average blood volume for adults: 5-6 liters
• • Blood is analyzed in the form of whole blood, plasma, or serum
• • Plasma - liquid portion of anticoagulated blood; contains the protein fibrinogen
• • Serum - liquid portion of clotted blood
• • Plasma
  • a comprises approximately 55% of the total blood volume.
  • It is a clear, straw-colored fluid that is about 91% water 9% dissolved substances
• Erythrocytes

  • Red blood cells
  • Are anuclear biconcave disks that are approximately 7.2 microns in diameter.
  • Erythrocytes contain the protein hemoglobin to transport oxygen and carbon dioxide.
  • Life span: 120 days
• Leukocytes

  • White blood cells.
  • provide immunity to certain diseases by producing antibodies and destroying harmful pathogens by phagocytosis.
  • Normal number: 4,500 to 11,000 per uL of blood.
  • Differential cell count - determines the percentage of each type of leukocyte.
• Neutrophils

  • the most numerous leukocytes (40-60%)
  • provide protection against infection through phagocytosis.
  • called "segmented" or "polymorphonuclear cells"
  • increases in bacterial infections
• Lymphocytes

  • the second most numerous leukocytes (20% to 40%)
  • provide the body with immune capability by means of B and T lymphocytes.
  • has a large round purple nucleus with a rim of sky blue cytoplasm.
  • The number of lymphocytes increases in viral infections
• Monocytes

  • largest circulating leukocytes (3% to 8%)
  • act as powerful phagocytes to digest foreign material.
  • The cytoplasm has a fine blue-gray appearance with vacuoles and a large, irregular nucleus.
  • A tissue monocyte is known as a macrophage.
  • The number of monocytes increases in intracellular infections and tuberculosis.
• Eosinophils

  • Red orange granules, and the nucleus has only two lobes. (1% to 3%)
  • detoxify foreign proteins and increase in allergies, skin infections, and parasitic infections
• Basophils

  • least common of the leukocytes. (0% to 1%)
  • The cytoplasm contains large granules that stain purple-black.
  • release histamine in the inflammation process and heparin to prevent abnormal blood clotting.
• Thrombocytes

  • Platelets
  • small, irregularly shaped disks formed from the cytoplasm of very large cells in the bone marrow called the megakaryocytes.
  • life span: 9 to 12 days.
  • average number: between 140,000 and 440,000 per uL of blood.
  • play a vital role in blood clotting in all stages of the coagulation mechanism
• Coagulation Section

  • Sometimes a part of the hematology section, but in larger laboratories it is a separate section.
  • Specimen: Plasma from light blue stopper tubes (sodium citrate) 
  • the overall process of hemostasis is evaluated; this includes : 
  • platelets - blood vessels 
  • coagulation factors - fibrinolysis 
  • inhibitors - anticoagulant therapy (heparin and coumadin)
• Blood smears

  • needed for the microscopic examination of blood cells that is performed for the differential blood cell count, for special staining procedures, and for non automated reticulocyte counts.
  • should be collected before other samples to avoid platelet clumping.
  • Dermal puncture
  • Venipuncture: EDTA (within 1 hour of collection)
  • smooth film of blood that covers approximately one-half to two thirds of the slide
  • does not contain ridges or holes
  • has a lightly feathered edge without streaks
• Discrepancy : Uneven distribution of blood (ridges)

  Possible Causes : 

  • Increased pressure on the spreader slide
  • Movement of the spreader slide not continuous
  • Delay in making slide after drop is placed on slide
• Discrepancy : Holes in the smear

  Possible Causes : 

  • Dirty slide
  • Contamination with glove powder
• Discrepancy : No feathered edge

  Possible Causes : Spreader slide not pushed the entire length of the smear slide
• Discrepancy : Streaks in the feathered edge

  Possible Causes : 

  • Chipped or dirty spreader slide
  • Spreader slide not placed flush against the smear slide
  • Pulling the spreader slide into the drop of blood so that the blood is pushed instead of pulled
  • Drop of blood starts to dry out owing to delay in making smear
• Discrepancy : Smear too thick and short

  Possible Causes : 

  • Drop of blood is too big
  • Angle of spreader slide is greater than 40 degrees
• Discrepancy : Smear too thin and long

  Possible Causes : 

  • Drop of blood is tog small
  • Angle of spreader slide is less than 30 degrees
  • Spreader slide pushed too slowly