Complete blood count Flashcards
What are the tests that are usually included in a CBC?
1) White blood count (WBC)
2) Red blood cell count (RBC)
3) Hematocrit (Hct)
4) Hemoglobin (Hb or Hgb)
5) Red blood cell indices
6) Differential WBC count or ‘diff’ and platelet count (possible or ordered seperately
What are the components in a Red blood cell indices test
1) Mean corpuscular volume (MCV)
2) Mean corpuscular hemoglobin (MCH)
3) Mean corpuscular hemoglobin concentration (MCHC) -
What is measure in a Mean corpuscular volume (MCV) test?
The Average red blood cell size
What is measure in a Mean corpuscular hemoglobin (MCH) test?
The amount of hemoglobin per red blood cell
What is measure in a Mean corpuscular hemoglobin concentration (MCHC) test?
The amount of hemoglobin relative to the size of the cell or hemoglobin concentration per RBC
What is the primary function of Red blood cells
To carry oxygen from the lungs to the body tissues and to transfer CO2 from the tissues to the lungs
Oxygen is transferred via the red blood cell by what?
Hemoglobin
How are RBC shaped and what are they shaped that way?
They are shaped like biconcave discs to enable the maximum O2 saturation of hemoglobin (the biconcave shape provides more of a surface area for exposure of hemoglobin to dissolved O2.
What is the metric by which RBCs are counted
RBC per cubic millimeter of blood
An increase in RBC is called
Polycythemia
What are situations in which an increase of RBCs is considered ‘normal’
1) High altitudes
2) After strenuous physical training
3) (not normal but…) Smokers have a higher RBC count than non-smokes
What is Polycythemia vera (what causes it)
An abnormal increase of RBC in the blood marrow not caused by physiological need (cause unknown)
What is an important consideration for someone with an abnormally high RBC count (why?)
Hydration is an important consideration when caring for a patient with a high RBC count. It’s important because a very high RBC mass will slow blood velocity and increase the risk of intravascular clotting
What is the general term for someone with a low RBC count
Anemia (can also result from a low hemoglobin count)
What are some causes of a decreased RBC count
1) Acute hemorrhage
2) Abnormal destruction of RBC
3) lack of substances needed for RBC production
4) Chemo or radiation sfx
What is a reticulocyte
An immature form of erythrocytes (RBCs)
What are is a normal reticulocyte count (in men and women)
Men - 0.5% to 1.5% of total # of RBCs
Women - 0.5% to 2.5% of total # of RBCs
What could be some causes of low or high reticulocyte counts
Low - cirrhosis, folic acid deficiency, bone marrow failure.
High - Bone marrow is responding to an increased RBC production. Also anemia or recent blood donors
Hematocrit aka…
“Hct”, “crit”, or PCV (packed cell volume)
What does Hematocrit determine?
the percentage of RBC in plasma.
If RBC and hemoglobin are normal. What would you estimate to be the approximate hematocrit in the blood?
Three times the hemoglobin.
For example: If a person’s hematocrit is 30%, he would have a hemoglobin of approx 10gm
What are the critical high and low values of hematocrit
Low - under 15% can result in cardiac failure
High - above 60% may result in spontaneous blood clotting
Is the hematocrit level relative to the % of RBC or total volume of blood?
RBC %. So if a person looses a good amount of plasma volume, the hematocrit level will go up. Over hydration will result in a lower hematocrit level.
In supplying packed RBC to correct anemia. How much of an increase in hematocrit levels should you expect
Hematocrit should rise approx. 3% per each unit transferred
How long does it take for the bone marrow to produce mature RBC
Approx 10 days
What is a hematocrit test done frequently for
To determine the extent of significant blood loss after a major hemorrhage
Why is testing hematocrit a good way to assess the extent of significant blood loss?
Because after a hemorrhage RBC and plasma are lost in equal proportions, but plasma (volume) is replaced a lot quicker (hours from intestines) than RBC (10 days). So a hematocrit hours after a hemorrhage will show a more accurate picture of the significant of the effect of blood lost.
What are the 2 types of hemoglobin subunits
Alpha and beta
How much O2 can each gram of hemoglobin carry?
1.34 ml of O2 per gram of hemoglobin
What is hemoglobin’s role in ECF
Acts as an important pH buffer
What contributes to a decreased hemoglobin
1) Blood loss and bone marrow suppression (go hand in hand with a lower RBC count)
2) Also those who have an abnormal type of hemoglobin.
3) Iron deficiency anemia (normal RBC but low hemo)
What is another term for iron deficiency anemia
Hypochromic anemia (less than normal color anemia)
What contributes to increased levels of hemoglobin
Anything that would contribute to an increased # of RBC circulating in the blood…
- polycythemia vera
- severe burns
- chronic obstructive pulmonary disease
- CHF
What are the critical low/high values of hemoglobin?
Low: under 5 g/dL may cause heart failure
Hight - over 20g/dl may cause clogging of capillaries due to hemoconcentration
How does erythrocyte indices help determine info on different types of anemia
It determines whether the RBC are of normal size or if they have a normal concentration of hemoglobin
How is Mean Corpuscular Volume (MCV) determined and what does a low/high reading determine
Determined by hematocrit divided by total RBC count
Low = cells are smaller than normal (microcytic)
High = cells are larger than normal (macrocytic)
What conditions are microcytic RBC seen in
1) Iron deficiency anemia
2) Lead poisoning
3) Thalassemia major and minor (genetic disease)
What conditions are macrocytic RBC seen in
1) Pernicious anemia
2) folic acid deficiency
What is it called when the MCV is within normal range
Normocytic
What kind of anemia can a person with normocytic anemia have
Anemia from an acute hemorrhage.
How is Mean corpuscular hemoglobin (MCH) determined
Weight of hemoglobin = hemoglobin divided by total RBC count x 100
How is MCH measured
The weight in of hemoglobin in an average cell is measured in pictograms (pg). MCH is reported in a percentage (hemoglobin in the RBC)
What erythrocyte indices determine if RBC are deficient in hemoglobin concentration
an MCHC less than 32% or an MCH under 27%
What are the two classifications (groups) of leukocytes
1) Granulocytes - have granules in cytoplasm
2) Non-granulocytes (agranulocytes)
What are two non-granulocytic WBC
Lymphocytes and monocytes
What kind of nuclei do lymphocytes and monocytes have
Non-lobular
What are three granulocytic WBC
Neutrophils, eosinophils and basophils
What kind of nuclei do granulocytes neutrophils, eosinophils and basophils have? (what are they also known as)
Multilobed nuclei (aka polymorphonuclear leukocytes or polys). Nuclei of neutrocytes are also segmented and they can also be called ‘segs’.
What is the lifespan of a WBC
13-20 days
What are immature WBCs released into the peripheral blood called
Bands or stabs
Define phagocytosis
Where WBC (leukocytes) surround and destroy foreign organisms
What are two measurements of WBC commonly done in a CBC
1) Total # of WBC in a microliter of blood (reported as an absolute # of “X” thousands of WBCs.
2) The percentage of each of the 5 types of WBC
What is the test to determine the percentage of the 5 different type of WBC called
A differential or diff. (reported in percentages)
What determines Leukocytosis
a WBC above 10,000
What is Colony stimulating factor (CSF)
a substance released by WBC in response to an acute infection, trauma or inflammation. It stimulates the bone marrow to increase WBC production
What can mask leukocytosis
corticosteroids
What is Leukopenia
A low WBC count
How is Leukopenia defined
When WBC falls below 4000.
What can cause leukopenia
1) Viral infections
2) Bacterial infections
3) Bone marrow disorders
What is the role of neutrophils
They are the body’s primary defense against bacterial infections and physiologic stress (severe burns or MI)
A decreased # of neutrophils is called
Neutropenia
What can cause neutropenia
1) Some bacterial infections (the # goes down instead of up) like typhoid fever or brucellosis
2) Many viral diseases
3) Many antineoplastic drugs (that fight cancer) that can produce bone marrow depression
What is an important consideration for someone with an abnormally high RBC count? (why?)
Hydration is an important consideration when caring for a patient with a high RBC count. It’s important because a very high RBC mass will slow blood velocity and increase the risk of intravascular clotting
The oxygen carrying ability of blood is directly proportional to?
… it’s hemoglobin concentration (not RBCs because they can have a varying amount of hemoglobin)
What is the physical structure of hemoglobin?
A molecure comprised of 4 subunits, each of which contains an iron containing pigment (heme) and a protein (globulin)
What is hemoglobin determination used to screen?
1) Anemia (diagnose, its severity and to assist in evaluating the patient’s response to anemia therapy
How does erythrocyte indices help determine info on different types of anemia?
It determines whether the RBC are of normal size or if they have a normal concentration of hemoglobin
What kind of anemia can a person with normocytic anemia have?
Anemia from an acute hemorrhage.
What erythrocyte indices determine anemia from acute blood loss?
MCV, MCH, and MCHC normal - Normocytic and normochromic anemia
What erythrocyte indices determine anemia from iron deficiency ?
MCV, MCH, and MCHC decreased - microcytic and hypochronic anemia
What erythrocyte indices determine pernicious anemia?
Increased MCV, variable MCH, and MCHC. Macrocytic anemia caused by vitamin B12 deficiency and folic acid deficiency
What are the two classifications (groups) of leukocytes?
1) Granulocytes - have granules in cytoplasm
2) Non-granulocytes (agranulocytes)
What are two non-granulocytic WBC?
Lymphocytes and monocytes
What is the test to determine the percentage of the 5 different type of WBC called?
A differential or diff. (reported in percentages)
Name the 5 types of Leukocytosis.
1) Neutrophilia
2) Lymphocytosis
3) Eosinophilia
4) Monocytosis
5) Basophilia
What is Colony stimulating factor (CSF)?
a substance released by WBC in response to an acute infection, trauma or inflammation. It stimulates the bone marrow to increase WBC production
What is blood determination is a sign of infection?
Leukocytosis
What can cause leukopenia?
1) Viral infections
2) Bacterial infections
3) Bone marrow disorders
What are Leukocytes critical low/high values?
Low: 30,000 indicates massive infection or serious disease like leukemia
What does ‘shift to the left’ mean in a WBC count?
An increased number of less mature neutrophils (bands or stabs) in the blood (indicating an infection is in progress)
What are eosinophils associated with?
Antigen-antibody reactions (allergic reactions like hay fever, asthma and drug hypersensitivity
What might cause a decrease in eosinophils?
Someone receiving corticosteroid drugs
What are basophils and what do they contain?
They are phagocytes and contain heparin, histamines and serotonin.
What are tissue basophils also know as ?
Mast cells
What are basophil counts used to analyze?
Allergic reactions
What can cause basophils to increase?
An alteration in bone marrow functions like leukemia or Hodgkin’s disease
What can cause a decrease in basophils?
Corticosteroid drugs, allergic reactions and acute infections
What are monocytes claim to fame and what do they do?
They are the largest cells in normal blood. They act as phagocytes and are the body’s 2nd line of defense against infection
What do phagocytic monocytes produce?
The antiviral substance - interferon
What diseases can cause a monocytosis?
TB, malaria, RM spotted fever, monocytic leukemia, chronic ulcerative colitis and regional enteritis
What are the primary components of the body’s immune system?
Lymphocytes
What are lymphocytes the source of?
Serum immunoglobulins and cellular immune response
Lymphocytes play an important role in?
Immunologic reactions
What can cause a decrease/increase in lymphocytes?
Increase - Viral infections and TB
Decrease - Lymphocytic leukemia, HIV, corticosteroids and other immunosuppressive drugs
What are platelets?
Cell fragments formed in the bone marrow that circulate throughout the bloodstream
What is the role of platelets?
They play a critical role in the body’s ability to help blood clot
What is a decrease in platelets called?
Thrombocytopenia
When is thrombocytopenia diagnosed?
When the platelet count goes below 50,000.
What can happen when the platelet count drops below 20,000?
Can result in spontaneous bleeding and death
