Hematology Flashcards
What is a Mean Cell Volume (MCV)?
Measures number and size of RBCs.
What are 10 direct measurements in a CBC?
PCV, hemoglobin, red cell count, mean cell volume, white cell count, plasma protein, platelet count, mean platelet volume, retoculocyte count, reticulocyte MCV.
What can a small retic MCV mean?
Small reticulocyte cell volume can mean that you have an iron deficiency anemia.
What procedures do we do microscopically for the CBC?
WBC differential, cell morphology, retic count (if anemic).
Why do we do a differential?
Because electronic counters can’t distinguish nucleated cells or bands from segmented neuts.
What is a red top tube for?
Serum sample, for biochem panels because no additives in tube.
What is the purple top tube for?
CBC because it has potassium-EDTA to prevent clotting and preserves cell morphology.
What must you be cautions with when using red and purple top tubes together?
Be careful that you don’t contaminate the red top sample with EDTA from the purple top. Will give abnormally high potassium, and very low calcium.
What is the green top tube for?
Specific tests because it contains heparin.
Hat is the blue top tube for?
For coagulations tests because it contains citrate.
What is the grey top tube for?
Good for if sample can’t be spun or looked at right away, especially where glucose is important. It contains fluoride to inhibit glucose metabolism.
What is the tiger-top tube for?
Serum separator tube.
How much blood does a CBC and biochem profile require?
5 mL
What is important to avoid with venipuncture?
Tissue contamination.
How do you handle blood for a CBC?
Analyze within one hour or make a blood film and refrigerate sample.
What happens if blood sits for 24+ hours at room temp?
RBCs swell resulting in elevated MCV.
How do you handle blood for a biochem profile?
Let sot for 15-30 minutes, centrifuge, separate serum and refrigerate until analysis. Freeze serum if can’t analyze within 2 days.
What does it mean to have yellow plasma?
If small animal, icterus. If large animal, can be due to carotene pigments associated with diet.
What does it mean to have white, milky serum?
Lipemia, likely due to postprandial collection OR can be from abnormalities in lipid metabolism.
What does red serum mean?
Hemolysis.
How can you get hemolysis?
In-vitro due to technique or presence of lipemia.
In-vivo due to hemolytic anemia.
How can you tell if hemolysis is in-vivo or in-vitro?
If PCV is low, likely in-vivo. If PCV doesn’t decrease, likely in-vitro.
Is plasma protein by refractometry an exact number?
No, it’s an estimate.
What will you see with plasma protein values in a lipemic sample?
Plasma protein will be artificially increased.
What values will artificially increase the plasma protein?
Urea, glucose, cholesterol and lipemia.
What should you do to follow up the plasma protein value obtained from the refractometer?
A biochemical measurement of albumin and globulin in serum. These two values should add up to total protein.
T/F: Increased albumin is not always due to dehydration.
False. Increased albumin is always due to dehydration.
What is suggested if total protein and the PCV are both elevated?
Suggests dehydration.
What is suggested if total protein and PCV are both decreased?
Suggests blood loss.
What 2 things are a blood smear essential for?
Differential cell count
Evaluating morphology of WBCs, RBCs and platelets.
What 5 things are required for a successful blood smear.
Quality of the smear In the right counting zone Recognition of morphologic abnormalities Recognition of artifacts Ability to interpret diagnostic significance.
How to you convert % of WBCs to absolute numbers?
Multiply the total nucleated cell concentration by the percentage of each WBCs type.
How do you evaluate platelets?
Should have 6-10/oif, check feathered edge for clumps, check size relative to RBCs (if they approach RBC size, they are called macroplatelets.
What are the 6 counting and sizing techniques done with a machine?
RBC Count (x 10^6/uL) MCV (fL) Nucleated cell count (uL) Differential cell count (uL) Platelet count (uL) Reticulocyte count (uL, fL)
What automated measurement is done using spectrophotometry?
Hemoglobin concentration (g/dL)
*Usually approx. 1/3 of the PCV
What factors can affect the hemoglobin concentration?
Intravascular hemolysis, lipemia, Heinz bodies
How do you calculate the hematocrit?
(MCV x RBC)/10 = Hematocrit
How do you calculate MCHC?
(Hgb (g/dL) x 100)/PCV = MCHC (g/dL)
Is the MCHC helpful?
Not particularly diagnostic. An increase tells you there’s a glitch somewhere because red cells can only hold so much hemoglobin.
What can cause an increased MCHC?
High readings caused by hemolysis, lipemia or presence of Heinz bodies.
What can cause a decreased MCHC?
May be due to iron deficiency, or due to presence of many reticulocytes.
What is a decreased MCHC usually associated with?
Regenerative anemia.
What is light scatter measurement?
Cells pass through a laser beam and the physical properties of the cells scatter the light to tell you the cell type.
What is impedence measurement?
Cells are suspended in an electrolyte medium that conducts electricity. Cells are poor conductors and deflections in current are proportional to the cell size.
What is a size distribution curve?
A curve for each cell type of each species that shows the number of cells above average, average and below average.
What is the normal size of dog RBCs?
60-72fL
What is the normal size of cat, horse and cow RBCs?
39-52fL
What is the normal size of sheep?
25-35fL
What is the normal size of llama RBCs?
21-29fL
What is special about camelid RBCs?
Higher MCHC and they’re oval.
What is the normal size of goat RBCs?
15-25fL
What is the normal size of human RBCs?
80-100fL
From largest to smallest, rank the domestic species by RBC size.
Dog > cat=horse=cow > sheep > llama > goat
What can cause RBCs to agglutinate?
Igs attached to the cell wall of RBCs will cause them to clump.
What is the red cell distribution width (RDW)?
Describes the relative width of the size distribution curve.
How do you calculate the RDW?
Standard deviations of most of the RBCs divided by the MCV.
How can reticulocyte concentrations be determined?
Flow technology or manually.
What do reticulocytes look like with Wright’s stain?
Polychromatics
What do certain stains to do the reticulocytes?
Cause the residual organelles to clump and be seen.
How do you count reticulocytes?
Count 1000 RBCs, percentage that are reticulocytes is multiplied by the RBC count to get an absolute retic count.
What are normal reticulocyte counts for dogs, cats, cows and horses?
Dogs: 0-60000/uL
Cats: 0-40000/uL
Cows: 0, but can respond
Horses: DO NOT RELEASE RETICULOCYTES
Above what number can we say that the cells are regenerating?
60000
How long do dog reticulocytes take to mature?
24-48 hours from release to maturation
How long do cat reticulocytes take to mature?
Trickier…
Aggregates become punctate (which are not counted)
Aggregate - punctate in ~12 hours
Punctates persist for ~12 days
What is a leukogram?
Numeric data + morphologic abnormalities.
What species has nucleoli in their normal lymphocytes?
Cows.
What suffix is given for reduced concentration?
“-penia”
What suffix(s) is/are given for increased concentration?
“-philia” or “-cytosis”
What is a “left shift”?
Increased concentration of bands
What does disorderly maturation tell you?
Consumption is severe or a neoplastic process is present.
What are the three toxic changes of leukocytes?
Increased basophilia
Dohle bodies
Cytoplasmic vacuolation
How significant is hypersegmentation?
Not very.
What is neutrophil degeneration?
Cytoplasmic vacuolation, nuclear swelling and cell lysis in neuts that are no longer in circulation.
List 4 inherited neutrophil anomalies.
Pelger-Huet Anomaly
Birman cat neutrophil granulation anomaly
Chediak-Higashi Syndrome
Lysosomal storage disorders with neutrophil granulation
What is a Pelger-Huet anomaly?
Failure of the neutrophil nucleus to segment. Can be mistaken for bands, but eos also fail to segment.
NOTE: It’s a heterozygous gene, homozygous die in utero.
What must you distinguish Pelger-Huet from (d/t granules in the lymphocytes)?
Lysosomal storage disease
What is Chediak-Higashi Syndrome?
Lysosomes fuse and look like large pink granules.
What does Chediak-Higashi cause with the coat?
Melanin granules also fuse and give the coat a grey colour.
What happens to the neutrophils in Chediak-Higashi?
They don’t function normally and don’t phagocytize or kill bacteria as effectively.
What happens to platelets in Chediak-Higashi?
Granules can be abnormal and animal may have a tendency to bleed.
What causes acquired lymphocyte vacuolation?
Plant toxin swainsonine (locoweed), inhibits lysosomal enzymes = acquired lysosomal storage disease.
What do you commonly see in ruminants that have inflammation and why?
Neutropenia because they don’t have a large pool of neuts in bone marrow reserve.
What species needs a huge inflammatory focus to cause a neutropenia?
Horses
What in cats will cause a very high neutrophil count?
Walled-off abscesses.
What does an excitement leukogram look like?
Lymphosytosis, can also see two-fold leukocyte concentrations.
What does a stress leukogram look like?
Lymphopenia, neutrophilia, eosinopenia
What 3 leukograms will have a neutrophilia?
Inflammation
Excitement
Stress
What should you see on a CBC with inflammation?
Left shift or neutrophilia 2x greater than the upper limit
What 2 diseases should be on your differential with a lymphocytosis?
Ehrlichia
Lymphoid leukemia
NOTE: Not all dogs with ehrlichia have a lymphocytosis.
Over what number of lymphocytes is it pretty safe to say you have a leukemia?
35 000
What are 3 causes for a neutropenia?
Consumption
Immune mediated destruction
Lack of production
What is the lifespan of a neutrophil?
6-8hrs
What causes a reversible bone marrow injury?
Viral injury
What causes an irreversible bone marrow injury?
FeLV
What are 3 causes for a lymphopenia?
Steroid response
Acute viral infectinos
Immunodeficiency (RARE)
What are 2 causes for a monocytosis?
Inflammation
Stress response
What are 3 causes for an eosinophilia?
Parasitism
Hypersensitivity
Lesions producing eosinophil attractants (eg. Mast cell tumor)
What doesn’t normally cause an eosinophilia?
RBC parasites
What causes a basophilia?
Usually accompanies an eosinophilia
