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