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