Exam 1: Week 1 Flashcards
Clinical Pathologist
A veterinary clinical pathologist is a veterinarian who studies diseases in animals, examines blood, tissues, and fluids, and is responsible for the accuracy of laboratory tests
Clinical pathology is…
what is hematology, biochem, and cytology
diagnostics for live animals
* hematology: look into blood
* biochemistry: look into organs
* Cytology: needle in mass or fluid from body cavity
Hemoglobin
Oxygen caryng molecule in red blood cells
reticulocytes
baby red blood cells
A reticulocyte is a young/immature erythrocyte which still contains ribosomes & mitochondria in the cytoplasm
diff types of stain, Wright=purp/blue other shows residual organelles
reference intervals
healthy and unhealthy and sometimes the numbers overlap, so take lab results with a grain of salt. somtimes animals fall in “tails” - look at the animal.
What questions does a CBC answer?
complete blood cell count
* is there anemia?
* is there inflammation?
* is there leukemia?
* platelets okay? Is there enough?
three tests that provide a good screening of the systemic health of a patient
- serum biochemical panel (tells you about organs)
- urine analysis (do not call kidney failure until you do this)
- CBC
Select the appropriate types of collection tubes that are used for CBC, biochemical profile, coagulation profile, and glucose when serum can’t be separated from clot.
CBC: purple
biochemical profile: red
coagulation profile: blue
glucose: gray
Recognize errors that can be introduced when incorrect tubes, collection methods, and storage methods are used.
incorrect tube errors: coagulation when you don’t want.
collection methods: not putting it up or taking out the serum in time, cells can bloat. sampling error can cause coagulaiton and an incorrect (low) platelet count.
storage methods: if frozen, sample can expand and ruin information. not putting in enough sample in a tube with EDTA can cause erythrocytes to shrink.
Describe the importance of, and method for, performing reticulocyte enumeration
importance? helps us to assess whether or not an anemia is regenerative.
method? add EDTA to blood stain, mix tube and incubate for 10 minutes, use drop to make blood film, let dry, examine.
to read? count 1000 red blood cells, categorize cells as either reticulocytes or normal cells, derive the percentage of reticulocytes, calculate absolute reticulocyte count.
RBC/ulx%retics=absolute retics/ul
When can errors happen during blood collection and processing?
There can be errors at every step during
* collection
* processing
* handling/shipping
* testing
* interpretation
Color coding of stoppers
- Red: no anticoagulant, Blood is expected to clot so that serum can be harvested for biochemical profile and many other tests. (use if you want serum)
- Red and grey: “tiger top”, used to separate serum from erythrocytes (RBCs) without transferring to a different tube.
- Lavender: contains the anticoagulant EDTA so it strongly chelates Ca++, preserves cell morphology, and used to collect blood for CBC and fluids
- Blue: contains the anticoagulant sodium citrate which weakly chelates Ca++ and is used to collect blood for coagulation testing and platelet counts
- Green: contains anticoagulant heparin, used to collect blood from large animal, avian, and reptile serum biochemical panels and used for specific tests like lead concentration
- Gray: rarely used, contains sodium fluoride which inhibits glucose metabolism
heparin
an anticoagulant that prevents thrombin from promoting fibrin formation and is in the green blood collecting tubes
Technique for filling tubes
- large vein: so you do not cause vein to collapse or shearing
- sharp needle: do not want tissue plug, that will lead to clotting - do quick shot up
- let vacuum do the work: cells can lyse if you do not let it go in gently
- 20G needle or up: avoid hemolysis
* discarded blood>citrate>serum>EDTA - immediately invert anticoagulant tubes
don’t break seal on tubes with stuff in it
sample handling procedures
Blood for CBC: either analyze within one hour or make blood film and refrigerate tube (don’t refrigerate blood film- condensation causes cells to lyse).
Don’t allow to freeze, freezing lyses cells.
If blood sits at room temp for 24 hours or more, erthrocytes swell and leukocytes will degrade.
PCV
packed cell volume
sample handling
what happens if your blood sample sits at room temperature for 24 hours or more?
erythrocytes swell resulting in increased MCV (mean cell volume).
some serum enzymes are not stable and activity will be artificially low if not meausured immediately or if the serum was not stored properly.
what is the difference between serum and plasma?
plasma has free fibrinogen and is anticoagulated.
serum only has enzymes and the ions, no fibrin, fibrin is down in the clot
MCV
mean cell volume
size of cell
chelate
to create a ring-like complex, or in loose terms ‘to grab and bond to’
What is the appropriate tube to collect blood in for a serum chemistry panel?
Red tube: it does not have an anticoagulant. blood is expected to clot so that serum can be harvested for biochemical profile ad many other tests.
Red and grey blood tube
also known as sure-sep or tiger-top
used to separate serum from RBCs without trnsferring serum to different tube
What is the appropriate tube to collect blood in for a CBC?
Lavender top:
Contains the anticoagulant EDTA
(ethylenediaminetetraacetic acid with a potassium salt) – strongly chelates Ca++
Preserves cell morphology
Used to collect blood for CBC & fluids
blood must be mixed well to prevent clotting
What is the appropriate tube to collect blood in for coagulation testing?
Blue top
Contains the anticoagulant sodium citrate - weakly chelates Ca++
Used to collect blood for coagulation testing and platelet counts
blood must be mixed well to prevent clotting
What is the appropriate tube to collect blood in for glucose determination if going to ship and can’t spin sample?
gray top tube:
it has sodium fluoride stops (glucose) metabolism
gray tube is rarely used
blood tube types
green top
Contains the anticoagulant heparin
prevents thrombin from promoting fibrin formation
Used to collect blood for large animal, avian, & reptile serum biochemical panels
Also used for specific tests such as lead concentration
What can you find in both plasma and serum?
enzymes, electrolytes, albumin and globulin.
Why are reticulocytes important?
Helps us to assess whether or not an anemia is regenerative
– If an anemia is regenerative, it means that the bone marrow is responding appropriately to the anemia by producing new, young erythrocytes
horses do not release reticulocytes from marrow space even with regeneration. in healthy cattle you will not find reticulocytes.
What are some reasons your bone marrow cannot produce reticulocytes?
cancer, iron deficiency, kindey failure (no erythropoeitin)
What are the two reticulocytes that cats have?
aggregate (clumped and purple), and punctate (punctates look more red). aggregates mature into punctates. that’s just a cat thing.
can take 10-12 days to mature. dogs only 24 hours.
cannot always see punctate reticulocytes and can get a wrong count.
What three lines are you evaluating in CBC
PCV, HGB, MCHC
What are monocytes?
Blood born macrophages
What is an erythrogram?
A whole blood analyses
What are the parameters of total red cell mass?
RBC (concentration of erythrocytes), HGB (concentration of hemoglobin in blood), PCV/HCT (% of whole blood that is erythrocytes.
MCHC calculation are described as…(what do retics look like)
“chromic”
hpochromic: decreased hemoglobin
hyperchromic: increased hemoglobin
normochromic:within reference interval
How are HGB and MCHC related?
HGB/PCV=MCHC
an animal can be anemic and still have a normal MCHC count even if HGB is low.
what is Melena?
black poop, digested blood in the poop. so bleeding within upper GI tract.
bright red blood in poop can mean bleading past small intestine
Another term for PCV
HCT
Another term for HCT
PCV
What is it called when your MCHC is low?
Hypochromic
What is proof of regenerative anemia?
reticulocyte count being higher than normal (0.0-1.0)
What is intestinal Leiomyosarcoma
don’t actually need to remember this
Smooth muscle cancer
Chronic blood loss into intestinal tract due to mass.
Iron stores eventually depleted
Decreased iron = decreased hemoglobin
Decreased erythrocyte hemoglobin = hypochromasia
anisocytosis
red blood cells that are of different sizes
What is goat blood?
poikilocytosis (difference in SHAPE)
what is rouleaux?
when RBC stack on top of each other. not seen in healthy ruminants, increased rouleaux with increased plasma protein, thought to be related to decreased negative charge on horse RBC surfaces.
stickiness to not stickiness:
horses more than cats more than dogs
How can you tell the difference between rouleaux and agglutination?
rouleaux will be dispersed in a saline dilution.
polychromasia
Polychromasia means you have more immature red blood cells than what’s considered normal
has polychromatophils (called so on a Wright stain) and reticulocytes
define macrocytosis
larger cells (on average)
can a lower than average PCV indicate anemia?
yes or no
when really low, yes
What kind of blood cell population has low MCHC?
A hypochromic population
What is RDW and what does it tell you?
Red cell distribution width.
A high RDW means that there’s variation in the size of your red blood cells beyond what’s considered normal. A high RDW may be a sign of anemia or a related condition.
Google:
A low RDW (below 10.2%) means that the red blood cells vary very little in size. One reason for a low RDW level is macrocytic anemia.
Do spherocytes have a central pallor?
spherocytes do not have a central pallor
Define a spherocyte
spherocytes are erythrocytes that antibodies attacked, took a munch out of, therfore taking its “flopability” and hence it becoming a sphere.
What is icterus
yellow color
jaundice in humans
True or false: bilirubin is the breakdown of hemoglobin.
true
intravascular hemolysis clinical sequelae (just read and familiarize)
Intravascular hemolysis results in release of cell free hemoglobin, RBC stroma, and nonstroma proteins. Free hemoglobin binds nitric oxide (NO) at rate 1000 times that of RBC. Hemoglobin scavenging leads to decreased bioavailability of NO and thus vasoconstriction and alterations in capillary response to hypoxia. RBC stroma, which is the cytoskeletal framework supporting hemoglobin, can also contribute to DIC pathogenesis via activation of platelets and coagulation cascade. RBC stroma has also been shown to increase blood pressure and is toxic to the glomerulus and renal tubule and thus can cause acute renal failure. Ultimately, increased cytokines and hypotension stimulate a compensatory sympathetic nervous system response contributing to renal, splanchnic, and cutaneous vasoconstriction that, in combination with pathophysiology described above, leads to shock and circulatory collapse.
Dic: disseminated intravascular coagulation.
extravascular hemolysis
happens in a macrophage’s belly.
think in relation to liver
define icterus
pre-hepatic hyperbilirubinemia and discoloration of tissue.
can be caused by hemolysis in the blood stream
what is microcystosis?
smaller cells (on average)
When MCV is low, what can you say about the cells?
they are microcytic
True or false: red blood cells keep dividing until they have enough homoglobin to get kicked out into the blood stream
true
What parameter can be used to evaluate variation in RBC size?
a. RBC
b. MCV
c. MCHC
d. RDW
e. Reticulocytes
d. RDW
How are the liver and spleen involved in RBC lysis?
RBCs lysed via the extravascular pathway are almost exclusively cleared in organs such as the spleen and liver.
