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42 Cards in this Set
- Front
- Back
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How is hematocrit calculated?
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MCV x RBC
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Which value is higher, PCV or hematocrit?
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PCV is usually slightly higher than HCT due to trapping of plasma between erythrocytes
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What are some common problems with automated hematology analyzers (this is why you should always look at a blood smear)?
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-cannot recognize morphologychanges
-clumped cells -small rbc's can be confused with platelets. this is most common in cats -nucleated rbcs counted as WBCs |
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What might diff quick not stain?
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mast cell granules
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What does new methylene blue stain?
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ribosomes
dna bacteria denatured hemoglobin |
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What are the two most common uses of new methylene blue?
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reticulocytes (with retained DNA)
heinz bodies |
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What should you look for at the feathered edge at 10x objective?
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platelet clumps
parasites neoplastic cells |
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what should you evaluate at the monolayer at 10x and then 40x?
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10x-evaluate cell number and arrangement
40x-evaluate WBC morphology and do a nucleated cell differential 100x-evaluate RBC and PLT morphologycen |
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What is often visible in the canine at the monolayer?
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central pallor
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What may turn cells really blue and cross link proteins, making cell morphology very difficult to see?
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exposure to formalin fumes
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What can happen i you underfill at a tube?
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it results in too much anticoagulant per volume of sample and the pcv can be falsely decreased, giving the appearance of anemia
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What can happen if you overfil the tube?
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it results in too little anticoagulant per volume of sample - sample can develop clots that interfere with analysis
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What is the recommended fill order of tubes?
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-blue top
-red top -purple top |
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What type o tube is the choice for turtles?
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a green top tube lined with heparin
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What is the hemoglobin concentration?
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it i approximately 1/3 the pcv or hct
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what does the hemoglobin concentration assume?
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it assumes that hemoglobin is in the rbc
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What type of things can falsely increase the hemoglobin concentration?
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hemolysis, lipemia, heinz bodies
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What are some causes of increased MCV?
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Macrocytosis
-reticulocytosis (usually with regeneration) -FeLV in cats -Congenital in poodles -Vitamin B12/folic acid deficiency (Giant Schnauzers) -RBC agglutination (artifact) |
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Causes of decreased MCV?
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microcytosis
-iron deficiency -immaturity -portosystemic shunt -Asian Breeds |
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What is usually ignored?
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MCH
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What is the mean corpuscular hemoglobin concentration?
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it is the average concentration of RBC HgB on a weight epr volume basis --> it is reported as a percentage
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What are causes of decreased MCHC?
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hypochromasia
-reticulocytosis -iron deficiency |
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How do you calculate the absolute reticulocyte count?
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retic percentage x rbc count = retics/microliter
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What are the two types of reticulocytes? Which one doyou cont in cats?
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aggregate and punctat. You only count aggegate in cats
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What are the causes of normocytic, normochromic anemia? (MCV and MCHC are within the reference interval)
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early blood loss or lysis
-simply not enough time to regenerate yet decreased red blood cell production -anemia of chronic disease -bone marrow damage -kidney problems |
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MIcrocytic Hypochromic anemia (decreased mcv and mchc)
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most commonly seen with iron deficiency
-chronic blood loss -decreased dietary intake -rarely seen with vitamin deficiencies |
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What are the causes of macrocytic hyopchromic anemia?
(increased MCV decreased MCHC) |
Generally seen with hemorrhage or hemolysis. Along with reticulocytosis is indicative of regeneration.
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What is the absolute reticulocyte count for regeneration in a dog? a cat?
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> 80,000 per micoliter in a dog
>60,000 per microliter in a cat |
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Do horses release stainable reticulocytes into the peripheral bloo?
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no
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Do ruminants release retics in health?
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no only in response to anemia
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What species have rouleaux formation?
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horses and to a lesser degree, cats
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Do cats have central pallor?
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no
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What type of rbc's do birds, reptiles, and fish have?
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nucleated RBC's
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What might cause stomatocytes?
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artifacts of thick blood smears
can be seen with overhydration of red cells and some drugs |
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What are acanthocytes?
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they most commonly occur with lipid abnormalities, which are often secondary to liver disease. They are most often seen in cattle and goats.
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what might cause echinocytes?
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crenation, secondary to prolonged drying times or even contact with glass, but they can also be seen in vivo with certain conditions likeuremia and snake bite envenomation.
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What are codocytes?
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target cells
-they reult from having an increased membrane to volume ratio -they are seen in low numbers in normal blood andare typically increased in regenerative anemia |
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When might you see dacrocytes?
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they are relatively uncommon in dogs, but are relatively common in camelids with iron-deficiency anemia
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When might you see schistocytes?
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they are typially associated with fragmentation anemias, which are often secndary to microvascular disease (dic, hemangiosarcoma, and vasculitis). These are more commonly noted in animals that have been splenectomized also, as teh spleen normally removes these membrane fragments from peripheral circulation.
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What causes eccentrocytes?
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these are bliste cells, they occur when the red cell membrane sticks to itself. They are most commonly seen with oxidative damage.
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What substances can ingestion cause heinz bodies?
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acetominophen
dried maple leaves zinc onions propofol rye grass |
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What causes spherocytes?
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these are red blood cells that havea normal MCV with decreased membrane surfae area. thy are most commonly associated with IMHA and are formed whn a splenic macrophage removes an antigen antibody complex adhered to the RBC membrane. the resulting hole in the membrane reseals wit the same amount of internal contents
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