Hematology I Flashcards
RBC
most numerous blood cell, approx 4.5 trillion per liter of adult blood, predominately hemoglobin, lifespan on 120 days, produced in bone marrow and destroyed in spleen
Normal RBC’s have a ______ shape
concave
Early RBC’s are formed from ___________
bone marrow stem cells
hemoglobin
protein that carries oxygen, comprises about 95% of RBC, size and color of RBC is directly proportional to amount of hemoglobin, composed of iron and protein chains
Can RBC’s replicate?
no
What is the lifespan of an RBC?
120 days
How do RBC’s interact with the spleen?
they are trapped and destroyed here. Due to RBC’s losing enzymes and surface membranes
How is hemoglobin broken down?
into heme and protein
How is heme broken down?
free iron and bilirubin
anemia
deficiency of RBC’s
How can severe anemia be clinically tested for?
pallor or pale appearance
What is the only way to test the severity of an anemia?
lab test
polycythemia
increase in RBC’s
CBC
complete blood count, most common test to evaluate blood cells, gives RBC, WBC, platelets, size and shape, lavender blue top with anticoagulant
What is the difference btwn a CBC and a CBC-diff?
a CBC-diff gives the the subset breakdown of the WBC composition by cell type
What is the purpose of the anticoagulant in the CBC tube?
it combats the clotting nature of the platelets
What are the 3 ways that a CBC can provide poor results?
- ) failure to mix tube with anticoagulant, tube clots
- ) inadequate filling of tube, anticoagulant dilutes sample, falsely low results
- ) possible increase RBC concentration from overexposure to tourniquet or standing
average RBC count X average cell size
MCV (mean cell volume)
hemoglobin in CBC
gold standard of CBC, measured on ability to absorb light
RBC count
cells counted by laser beam as they pass through a sizing chamber, also determines size of cells
RBC indicies
most useful way of determining RBC size and hemoglobin content, also called a MCV
hemocrat in %
____________
RBC content in millions per uL
MCV
What two tests rarely provide additional information to the MCV?
- ) MCH
2. ) MCHC
RDW
standard deviation on the MCV, measures uniformity in size of RBC, normal RDW often excludes iron deficiency, high RDW has a huge differential diagnosis
As EPO increases, so should _______
production of new RBC’s
reticulocyte count
most reliable measure of rate of RBC production, reported as percentage of total RBCs, highlights immature RBCs
What should be the response to anemia?
normal bone marrow increases RBC production, therefore increasing reticulocyte count
peripheral blood smear
used when etiology of anemia is unclear, not a direct diagnosis of disorders, guides further testing
bone marrow examination
bone marrow and aspirate and biopsy is end all and be all test, can confirm diagnoses, done in pelvic crest, biopsy is performed simultaneously, patient not sedated
iron deficiency
most common cause of microcytic anemia, occurs in 8% of children and menstruating women
iron tests measure both ________ and ___________
deficiency and overload
hemachromocytosis
iron overload
serum iron
measures iron that is bound to transferrin, provides indirect measure of rate of delivery to tissues, iron levels are up to 40% higher in morning than later in day, affected by menstrual bleeding
Should a patient take a iron containing medication on the morning of the blood draw?
no
serum levels can be low in ___, ____,and ____
acute inflammation
liver disease
nephritic syndrome
[transferrin]
iron transporting protein, measured directly or estimated using TIBC (total iron binding capacity), production is inversely related to body stores
low body stores of transferrin =
high transferrin
high body stores of transferrin =
low transferrin
How can you estimate the [transferrin]?
use a TIBC (total iron binding capacity)
serum ferritin
iron protein complex containing 23% iron, directly related to total iron stores, good marker for iron deficiency, widely distributed in the tissues
high body stores of ferritin =
high ferritin
low body stores of ferritin =
low ferritin
What can tissue damage falsely elevate?
serum ferritin levels
anemia
decrease in the amount of hemoglobin, most patients experience a decrease in [RBC] upon hospital admittance due to fluid moving into vessels, most common RBC disorder
What are the 2 mechanisms of anemia?
- ) decreased RBC production
- ) decreased RBC survival
*careful balance between RBC production and survival
microcytic anemia
decreased RBC size indicates defective synthesis of hemoglobin, associated with hypochromia, caused by iron deficiency and thalassemia, lead toxicity in young children
iron deficiency
most common cause of anemia, results from decreased iron intake or increased loss of iron due to chronic blood loss, early deficiency depletes bone marrow and cellular iron stores, serum ferratin levels drop, best test for Fe deficiency in normal adults is ferratin
thalassemia
2nd most common reason for microcytic anemia, inherited defect in the genes controlling globin chain synthesis, common in SE Asians and Africans, both alpha and beta, produces very small RBC’s
alpha thalassemia
disorder common in persons of African ancestry, less O2 delivery to tissues, deficiency causes deletion of hemoglobin S chains
beta thalassemia
deletion or reduction in the beta chain, produces decreased hemoglobin synthesis and microcytosis, hemoglobin A chains affected
lead poisoning
usually seen in children, zinc almost always increased in anemia due to lead poisoning, zinc : 1/lead
macrocytic anemia
commonly due to B12, folate deficiency, or myelodysplastic disorder, large cells, high MVC with or without anemia often present with alcohol abuse or liver disease
anemia in renal failure
defective production of EPO, degree of underproduction directly related to progression of disease, end stage renal disease/failure will produce virtually no EPO
synthetic EPO is available, however there is a high risk for _________
cancer
anemia of chronic disease
pathogenesis unknown, bone marrow resistant to EPO, serum ferratin is low or increased
bone marrow replacement
large percentage of bone marrow is replaced by abnormal cells, bone marrow biopsy needed for diagnosis, due to malignancies
aplastic anemia
failure of bone marrow due to decreased production, accompanied by low WBC and platelets, causes include cancer, chemotherapy, medications, virus
normocytic anemia due to hemolysis
10% anemia due to decreased RBC survival, MCV normal or slightly increased, intrinsic or extrinsic, body kills RBC’s
hemoglobinopathies
RBC’s under stress, sickle due to environment or illness, 1 out of 500 African persons, mutation in beta chain
glucose 6 phosphate dehydrogenase deficiency
causes hemolysis of RBC when exposed to infection or oxidant drugs
autoimmune hemolytic anemia
part of autoimmune diseases such as lupus, can also be due to drugs that attach to RBC membranes, for antibody against self, antibody + RBC = destroyed by spleen
hemolytic disease of the newborn
mom produces antiobodies, attack RBC’s of baby
polycythemia
increase in RBC mass over normal, increased hemoglobin or hematocrit, less common than anemia
secondary polycythemia
increased RBC production due to overproduction of EPO, causes renal cell carcinoma, renal cysts
polycythemia vera
EPO levels usually decreased, inappropriate overproduction of RBC’s, RBC up, WBC up, platelet up, spleen is overworked, platelets usually increased along with WBC’s
