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what are the purposes for lab testing?
- aid in diagnosis
- evaluate patients condition
- evaluate effects of treatment
- prognostic indicator
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list the tests that we can run
cell counts, morphology, chemistries, cytology, coprology (poop), serology (serum), culture & sensitivity, toxicology
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where are the different blood collection sites
jugular vein, cephalic vein, wing vein, femoral/saphenous vein, ear vein, caudal (tail) vein, toe nail
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how much blood can we take?
up to 20% of total blood volume
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what is a dogs total blood volume
90ml/kg
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what is a cats total blood volume?
70ml/kg
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why do vacutainers give a better sample?
- once thru needle
- less trauma to cells
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what is plasma?
the liquid portion of whole (unclotted) blood
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what does anticoagulant used to prevent?
clotting
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what does plasma contain?
soluble clotting factors and fibrinogen
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what is serum?
whole blood, no anticoagulant
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to get serum or plasma...
- centrifuge blood tube at moderate speed for 10 minutes
- draw off the plasma or serum
- label the tube with patient ID, doctor name, and date
- then use, refrigerate, or freeze
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define heparin
blocks numerous clotting factors from working
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what should we NOT use heparin for?
blood smears
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what is the lavender top tube used for?
anticoagulant...keeps blood from clotting by binding the calcium together
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what is EDTA?
lavender top tube
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when should a smear be made when using an EDTA? and why?
- within 30 minutes
- bc artifacts will appear in the WBC, platelets will clump together, & vacuoles will appear in the lymphocytes and they will be confused with monocytes
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what is in the green top tube?
heparin
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what animals are the green top tubes mainly used for?
avian and reptiles
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what are the green top tubes not used for mammalian hematology?
causes the platelets to clump and distorts the WBC
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what are the two types of heparin?
lithium and sodium
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what are the blue top tubes and what are they used for?
- sodium citrate
- used for coagulation profiles
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what are the red top tubes used for?
- used when we need serum
- no anticoagulant in them
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what are the tiger top tubes?
- serum-separator tubes
- makes drawing off serum easier
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what can cause inaccurate results?
- poor sample obtained
- poorly preserved sample
- incorrect sample used
- sample handled incorrectly
- equipment malfunction
- clerical errors
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what are the advantages to in-house testing?
- fast results
- you can control the sample
- fewer artifactual changes
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what are the disadvantages of in-house testing?
- requires an investment in equipment and supplies
- requires trained staff
- must have quality control procedures
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what are the advantages to outside labs?
- some tests can be done cheaper
- only place for certain tests
- experts are available for consulting
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what are the disadvantages for outside labs?
- takes time to get results
- tests or reports may be lost
- usually need a large volume of blood to do tests
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List the different sites for blood collection commonly used in dogs, cats, cows, rats, rabbits, and horses.
- Dog - jugular, cephalic, and lateral saphenous
- Cat - jugular, cephalic, and medial saphenous
- Cow - jugular and caudal (tail)
- Rat - caudal (tail)
- Rabbit - ear
- Horses - jugular
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What are the differences between plasma and serum?
- plasma has clotting factors and serum does not
- to get serum you have to let blood coagulate
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How can a negative result be beneficial diagnostically?
it gives you a rule out diagnoses (rules out different possibilites)
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List the advantages of in-house testing
- fast results
- less artifactual changes
- we can control the sample
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List the disadvantages of in house testing
- expensive equipment needs to be purchased
- must have trained personnel
- must have quality control procedures
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List the advantages of outside lab testing
- some tests may be cheaper
- there are some tests that can only be performed in an outside lab
- experts available for consulting
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List the disadvantages for an outside lab testing
- takes time to get results
- tests or results may be lost or mixed up
- need larger samples of blood
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Describe the appearance and indicate the causes of lipemia
- Appearance: white or pinkish-white
- Causes: postprandial sample, liver disease, diabetes mellitus
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Describe the appearance and indicate the causes for hemolysis
- Appearance: red
- Causes: excess pressure when drawing blood, rough handling, injecting blood too fast into tube, moisture in syringe or tube, intravascular problems (osmotic imbalance, hemolytic bacteria, incompatible transfusion, autoimmune disease)
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Describe the appearance and indicate the causes for icterus
- Appearance: Brownish yellow
- Causes: Hemolyic anemia, liver problems, cholestasis (blockage of bile and backs up into the blood stream)
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How will excitement affect CBC results?
it will cause an increase in RBC, WBC, platelets, and glucose
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What does the purple-top contain? What is it used for? What liquid would result from spinning it down?
- Contains: potassium EDTA
- Used for: mammalian hematology
- Result: plasma
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What does the green-top contain? What is it used for? What liquid would result from spinning it down?
- Contains: heparin (lithium and sodium)
- Used for: avain and reptile hematology
- Result: plasma
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What does the blue-top contain? What is it used for? What liquid would result from spinning it down?
- Contains: sodium citrate
- Used for: coagulation profiles
- Results: plasma
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What does the red-top contain? What is it used for? What liquid would result from spinning it down?
- Contains: nothing
- Used for: when we need serum
- Results: serum
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How to determine the maximum amount of blood that should be taken from a dog? From a cat?
- Multiply the weight in kilograms by either 70 (cat) or 90 (dog)
- Then multiple that number by 0.20
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Define cytology
the study of cells
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Define serology
the study of serum
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Define morphology
the study of what cells look
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Define toxicology
the study of toxins in the body
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Define coprology
the study of poop
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What should be placed on the patient's skin between a venipuncture site and your finger, after you have drawn blood?
clean dry cotton
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In which domestic species is the ear vein commonly used for venous access?
rabbits
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In which species is the tail vein commonly used for venous access?
rats and cows
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In which species is the jugular vein commonly used for venous access?
horse, dog, cat, cow
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In which species is the vena cava commonly used for venous access?
pig
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Are vacutainer sleeves reusable?
yes
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List four ways to fill a capillary tube
- from vein
- from vacutainer
- from needle hub
- from syringe & needle
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What are the problems with clipping a toenail for blood collection?
painful for the patient and hard to get the bleeding to stop
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What does plasma contain that serum does not?
clotting factors and fibrinogen
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What is the difference between a red-top and a tiger-top tube?
a tiger top tube has a serum separator to make drawing off the serum easier
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How long should whole blood in a red-top tube sit prior to spinning it down?
20 minutes to allow it to clot
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How long should the blood be spun down?
10 minutes
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Why must you avoid freezing cells?
it causes the RBC to lyse
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Which anticoagulant is preferred for mammalian blood smears?
EDTA
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How full should you fill a vacutainer that contains an anticoagulant? Why?
- full to within 10% of capacity
- because if not then the blood will become diluted with the anticoagulant
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Why is heparin not good for mammalian hematology?
it causes the WBC to distort and the platelets to clump
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If you can't run bloodwork immediately, what should you do with the sample and why?
put it in the refrigerator to reduce artifactual changes in the blood
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