The Complete Blood Count Flashcards
How is hemoglobin measured?
Spectrophotometrically. They lyse RBC and convert hemoglobin to cyanmethemoglobin and measure the absorbance of wavelengths at 525 or 540nm.
Define: Hematocrit
Volume of whole blood is occupied by red cells.
How do you calculate hematocrit?
Hct (%)= (RBC X MCV)
True or False: Red blood cells are fairly constant throughout life.
False. Physiological variables affect one’s RBCs include age, sex, and altitude.
What is erythrocytosis?
More than the expected number of red cells for one’s age
How does an aperture impedance work?
An electrical current is established across an aperture when cells pass through and causes a voltage surge. Pulses are directly related to the size of the cell.
What is mean corpuscular volume?
The average volume of a red blood cell
How do you calculate MCV?
MCV= ((HCT * 10)/ RBC)
What is Mean Corpuscular Hemoglobin?
The MCH is the content (weight) of Hgb of the average red cell
How do calculate MCH?
MCH = Hgb / RBC
What is mean corpuscular hemoglobin concentration?
Average concentration of Hgb in a given volume of packed red cells
How do you calculate MCHC?
(Hgb/Hct) * 100
What is red cell distribution width?
Measure of the variation in size of the red cells and will be proportional with the width of the histogram. It is expressed as a percentage.
What are reticulocytes?
Immature red blood cells that retain mRNA and ribosomes. 1-2 days afterr being released from bone marrow they lose RNA and organelles
What stain can you use to visualize reticultocytes?
Supravital stain- it aggregates the ribosomes and other organelles
How do you express nucleated RBCs?
Nucleated RBCs / 100 WBCs
Do platelets vary with sex or age?
No
What is it called when you have too few platelets?
Too many?
Thrombocytopenia
Thrombocytosis
What is measured using an impedance transducer?
RBC, Hct, PLT
When are white counts the most variable?
In childhood. They don’t very much after puberty
What is measured using a flow cytometer?
Platelets, Nucleated RBC, Percent white cells, reticulocyte percent, and heme progenitor cells
What do mononuclear cells refer to?
Lymphocytes and Monocytes
Describe the appearance of neutrophils.
Cytoplasm: Acidophilic with fine granules
Nucleus: Clumped chromatin with 2-5 distinct lobes connected
Too few: Neutropenia
Too many: Neutrophilia
*The most abundant adult white cell
Describe the appearance of lymphocytes
Cytoplasm: Very scant cytoplasm
Nucleus: Round dense chromatin
Too few: Lymphopenia
Too many: Lymphocytosis
*Most abundant white cell in young children
