MLS LECTURE 8 Flashcards
Define hematology:
Is the science or study of blood and blood forming tissues (bone marrow)
What is blood composed of?
Plasma& cells
Plasma is:
The flu d portion of the colood & is 90% water and 10% protein (mostly albumin & globulins) , carbohydrates , vitamins, hormones, enzymes, lipids, electrolytes (like salt), clotting factors, and trace metals
What are the cells and what do they consist of?
They are formed elements of blood. They consist of: erythrocytes, leukocytes, and thrombocytes (platelelts which are cell fragments )
hematology examination are usually:
Visually diagnostic
When is a major contributor used?
To solve a diagnostic problem & When they need to figure out what’s wrong with the patient.
Define the CBC test:
The complete blood count test is a routine hematology examination of the formed elements of the blood. it is the most commonly ordered lab test
The CBC will be composed of:
- WBC count
- RBC count
- hemoglobin (hgb)
- hematocrit (hct)
- platelet count (plt)
- RBC indices (mcv, mch, much, rdw)
- automated 3-or 5- part differential
State the meaning of erythrocytes
Red Blood cells or RBC are small biconcare non-nucleated disks ( doughnut shaped with a depressed center rather than a hole they are 7-8 um in size
Where do erythrocytes usually form?
Bone marrow
When is the CBC with manual differential usually ordered?
When tha various types o WBCs need to be analyzed
Usually done on a peripheral smear
What’s a peripheral smear?
It is a fixed stained thin smear of blood on a microscope slide. The attack will then load the slide on the microscope.
What does the peripheral smear do?
- Evaluate the size and morphology of RBC. WBC, and platelets.
-evaluate the type and relative numbers of the different types of WBCs. (By counting 100 WBC and figuring out how many of them are neutrophils, lymphocytes, monogtes, etc…) - help detect
When are peripheral smear often performed?
It is often performed when CBC with a normal diff has been specifically ordered.
What is the function of erythrocytes?
They have the function of carrying oxygen to the tissues of the cells of the body
Who is the oxygen carrier?
Hemoglobin
True or false: the lifespan of RBC is approximately 125 days
False; 120 days
Hemoglobin (Hgb) is:
A substance contained in RBC that provides a direct indication of the oxygen transport capacity of the blood (since it is a protein that carries oxygen).
It is usually low in anemia patients
Hemoglobin and hematocrit
Define “hematocrit (Hct)”
Is the percentage volume of blood that is composed of erythrocytes. Or is the percentage of RBC.
What are the 4 component the RBC indices contain?
MCV ( mean cell volume)
MCH (mean cell hemoglobin)
MCHC (mean cell hemoglobin concentration)
RDW (red blood cell distribution width )
Define RBC indices
It assess the characteristics of RBC and are useful in the evaluation of anemia, polycythemia, and nutritional disorders (iron deficiency anemia, B12, folate deficiencies)
What does the MCV do?
MCV or mean cell volume estimates the average volume of RBC and is clinically most useful of the RBC indices
How can we calculate the mean cell volume?
Either:
From the hematocrit and RBC
Or:
Directly from by CBC analyzer
What’s the difference between macrocytes and microcytes
Macrocytes are abnormally large cells that have an increase in mean cell volume while microscytes are abnormally small cells that have a decrease in mean cell volume.
Where are microcytes found?
Microcytes are usually found in iron deficiency anemia.
They are commonly found in B12 deficiency and/or folate deficiency
Macrocytes
Is the average weight of hemoglobin in RBC.
MCH / mean cell hemoglobin
When do the mean cell hemoglobin increase and when is there a drop/decrease in it?
Increase: folate deficiency
Decrease: iron deficiency anemia which corresponds with hypochromic
Which part of hemoglobin carries oxygen?
Iron molecules
How many globin chains are there in a single hemoglobin molecule?
4
Define mean cell hemoglobin concentration (mchc)
The average amount of hemoglobin per volume of RBC.
Is the only anemia in which mchc is routinely low in
Iron deficiency anemia
Is an indication of the variation of RBC size that is termed anisocytosis.
Red Blood cell distribution width (rdw)
True or false: anisocytosis= elevated RDW.
True
The difference of iron deficiency anemia and thalassemia (in terms of rdw)
Iron deficiency anemia will usually show a high RDW with microcytes while thalassemia will usually show a normal or low RDW with microcytes
