Basic examination of blood. Investigation and classification of anaemia.Thrombocytosis and thrombocytopenia. Flashcards
What is a red blood cell count? How is it performed?q
A red blood cell (RBC) count is a blood test that tells you how many red blood cells you have. Red blood cells contain a substance called haemoglobin, which transports oxygen around the body.
How are they performed?:
• Manual method
• Automated CBC Parameters
• Electrical Impedance (The Coulter Principle)
The cells are counted and sized by the pulse generated.
Sweep flow ensures that the cell is counted once by
preventing backflow.
How is a blood smear prepared and stained?
A thin smear being prepared. Place a small drop of blood on the pre-cleaned, labeled slide, near its frosted end. Bring another slide at a 30-45° angle up to the drop, allowing the drop to spread along the contact line of the 2 slides. Quickly push the upper (spreader) slide toward the unfrosted end of the lower slide.
How are erythrocytes evaluated using a blood smear?
Erythrocytes (RBCs):
- Evaluated in an area of stained slide where red cells evenly distributed and do not overlap (feathered edge).
- After being stained, is circular cell with distinct and smooth margins and a pinkish color.
- In center of cell is an area of central pallor. Should be fairly uniform in shape and size. Have no nuclear inclusions.
• To evaluate the size of an RBC without a micrometer, compare the RBCs with the nucleus of a SMALL lymphocyte. If the RBCs are smaller than the
nucleus of a small lymphocyte, it is most likely a microcyte. If the RBCs are larger than the nucleus is larger than the nucleus of a SMALL lymphocyte,
then it is most likely a macrocyte.
What are CBC parameters?
The CBC report consists of 24. parameters; total WBC, total RBC, HGB, Htc, mean. cell volume (MCV), mean cell hemoglobin (MCH), MCH concentration (MCHC), red cell distribution. width (RDW)-standard deviation and RDW-coefficient.
A complete blood count (CBC) is a blood test used to evaluate your overall health and detect a wide range of disorders, including anemia, infection and leukemia. A complete blood count test measures several components and features of your blood, including: Red blood cells, which carry oxygen.
What units are WBCs reported in?
X 109/L
Calculated: Impedance count
What units are RBCs reported in?
X 109/L
Calculated: Impedance count
What units is HGB reported in?
g/L
Method of determination: Colorimetric absorbance in proportion to hemoglobin
What units is MCV reported in?
fL
Method of determination:
From RBC histogram,
#of RBCs X size of RBCs X cal constant OR Calculated: HCT X 100
RBC
What units is HCT reported in?
%
Calculated: RBC X MCV
100
What units are MHC reported in?
Pg
Calculated: HGB X 100
RBC
What units is MHCH reported in?
g/L or %
Calculated: HGB X 100
HCT
What units is RDW reported in?
%
Impedance count(from histogram)
What units are platelets reported in?
X 109/L
Impedance count
A normal platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. Having more than 450,000 platelets is a condition called thrombocytosis; having less than 150,000 is known as thrombocytopenia. You get your platelet number from a routine blood test called a complete blood count (CBC).
What is the RDW? What are its clinical implications?
Red Cell Distribution
Width
HIGH: >14.6%
•Mixed population of RBCs
•Immature RBCs tend to be larger
What are the red cell indices?
Average red blood cell size (MCV)
Formula = MCV = (Hematocrit %) / (RBC x 1012/L) x 10
Hemoglobin amount per red blood cell (MCH)
Formula = MCH = (Hemoglobin in g/dL) / (RBC x 1012/L) x 10
The amount of hemoglobin relative to the size of the cell (hemoglobin concentration) per red blood cell (MCHC)
Formula = MCHC = (Hemoglobin in g/dL) / (Hematocrit %) x 100
Red cell distribution width (RDW)
