Hematology Course Overview Flashcards
What is the difference between serum and plasma, and what is the buffy coat layer of centrifuged blood?
Plasma - Contains albumin, immunoglobulins, coagulation factors, and complement system
Serum - plasma minus clotting factors
Buffy coat - layer of WBCs - mainly neutrophils and lymphocytes
What zone of a slide do we read in a blood smear?
The very thin zone called zone of morphology - on the edge of the smear, where the cells are less densely packed
What test is normally ordered as a first step of working up a blood disorder? How do you know the relative split of cell types?
Complete Blood Count (CBC)
to see what specific cells are present, order a differential
What is the lifespan of an average neutrophil, platelet, or RBC?
Neutrophil - 6-8 hours
Platelet - 7-10 days
RBC - 120 days
Where does hematopoesis first begin and where does it ultimately move to / when?
Starts in yolk sac, then liver / spleen, before finally moving to bone marrow
Moves to primarily bone marrow / some lymph nodes by birth
How is bone marrow directly accessed in clinic? What is the myeloid:erythroid ratio?
Bone marrow biopsy / aspiration via a needle in the iliac crest
-> very painful procedure
Me = 2:1
Two myeloid for 1 erythroid cells
What three things do we expect to see in a bone marrow core biopsy?
- Fat cells
- Hematopoeitic cells
- Bone Trabeculae
What measure are we trying to estimate in bone marrow core biopsy and how is this done?
Cellularity of bone marrow -> what percent of the non-bone areas are hematopoeitic stem cells (and not fat)
Subtract Fat % from cellularity
I.e. Aplastic anemia is all fat = 0% cellularity
Why does pallor tend to occur in anemia?
Blood is shunted away from skin to vital organs
What changes in the eye occur due to anemia?
Retinal hemorrhage can occur due to hypertension caused from high output cardiac state to maintain oxygenation in a state of anemia
When is the only time in which we care about whether an anemia is hypochromic / normochromic and how is this measured?
When the anemia is microcytic or normocytic. We don’t care for macrocytic.
Measured via mean corpuscular hemoglobin (MCH)
MCH < 27 pg = hypochromic
MCH > 27 pg = normochrombic
What are the three size classifications of anemia and the cutoffs?
Microcytic: MCV < 80 fL
Normocytic: MCV 80-99 fL
Macrocytic: MCV > 99 fL
What is the normal reticulocyte percentage and what does it suggest if it is not raised in an anemic patient?
0.5-2.5%
Suggests impaired marrow function or lack of erythropoietin stimulus
What is it important to look at a blood film always if a patient is anemic, even if MCV is normal?
In some cases as in mixed iron deficiency and folate/cobalamin deficiency, the MCV can be normal but there may be a “dimorphic” appearance with some microcytic cells and some macrocytic due to the two deficiencies
Also, WBC / platelet abnormalities will be obvious
What are anisocytosis and poikilocytosis?
Anisocytosis - variations in size
Poikilocytosis - variations in shape
Cell variations seen in anemia
What are Heinz bodies?
Oxidized, denatured hemoglobin precipitating in aggregates
-> common in G6PDH deficiency
How are reticulocytes and Heinz bodies shown as blue? Why are reticulocytes blue?
Methylene blue stain (supravital staining)
Reticulocytes are blue because they are new RBCs and still have some residual RNA which stain blue
What are Pappenheimer bodies?
Accumulations of iron within the RBC, often seen in sideroblastic anemia
What is a Howell-Jolly body and when is it seen?
A DNA remnant in an RBC normally removed by the spleen
It is seen in patients with Sickle cell disease or Hereditary spherocytosis post-splenectomy.