Hematology

Cards (23)

  • 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