Hematology Midterm (2)

what is hematology?

the study of blood and the tissues responsible for formation, storage and circulation of blood cells

**includes the study of liquid, cellular components and tissues

the most common use for hematology is

to screen the general health of a patient

three components of the blood

1. heavy/ packed RBC: bottom

2. lighter WBC/ buffy coat

3. plasma on top

what is one of the fastest and first blood evaluations preformed and what does it tell you

PCV/ HCT

hydration status/ anemia

**low is abnormal

slight pink to red color in buffy coat due to

1. did not centrifuge appropriate length

2. RBC are smaller then they should be (indicating anemia)

gross observation of what layer provides a subjective estimate to WBCs present

buffy coat

plasma color varies due to

-species

-diet

-physiological or pathological conditions

possible color changes of plasma and cause

1. bright yellow: gallbladder, liver or hemolysis

2. pale: dehydration

3. red: hemolysis

serum

fluid portion of blood remaining after the sample is allowed to clot

red tube vs purple tube

red: serum

purple: plasma

seven formed elements found in blood

1. RBCs

2. neutrophils

3. basophils

4. eosinophils

5. lymphocytes (agranulocytes)

6. monocytes (agranulocytes)

7. platelets

mammal RBC shape

disk shaped, non nucleated and pink-salmon-red color

camel, llamas, and other camelids have what shape RBCs

oval without central pallor

birds, reptiles, amphibians and fish have what shape RBCs

oval and nucleated

neutrophil characteristics

1. most common circulating WBC in domestic species

2. larger than RBC

3. single nucleus with 3 to 5 lobes

4. faint blue or pink cytoplasm with pink granules

eosinophil characteristics

1. absent or low presence in healthy animals

2. similar in appearance to neutrophils but segments are less defined

3. granules attract eosin which is a red dye

4. bright red to orange granules in the cytoplasm

when are eosinophils most commonly increased

-parasitic infection

- allergic reaction

-inflammation

basophil characteristics

1. rarely seen

2. increased numbers in rabbits and horses*

3. light purple cytoplasm, elongated nucleus

**similar to mast cells

lymphocyte characteristics

1. most common WBC in ruminants and lab animals

2. smallest WBC and barely larger than RBC

3. have ability to change size and shape when stimulated

monocyte components

1. largest of WBCs

2. nucleus is pleomorphic (many shapes)

3. cytoplasm is abundant with bluish gray foamy appearances

4. vacuoles present

what kind of platelet is most commonly seen in cats

macroplatelet

clumped platelets are due to

aggressive venipuncture

blue top use

- contatins sodium citrate for coagulation profiles

- provides information on clotting factors and values of clotting proteins

gray top use

-diatomaceous earth or kaolin for activated clotting time

-can see how long it takes for blood to clot

amount of blood needed for purple/ red top

purple: to the top

red: 1 mL

proper transfer of blood to tube

1. Remove stopper from the second tube

2. Remove the needle from syringe

3. Gently press the plunger on the syringe allowing blood to run down the side into the vial

if there is a delay between collection and analysis

samples should be refrigerated (if not analyzed within 30 minutes to an hour)

before analysis if refrigerated

1. refrigerated samples must be brought to room temp

2. inverted

3. older than 24 hours should not be used

blood smear guidelines

1. made prior to refrigeration

2. fresh blood after collection

3. from a well mixed anticoagulant tube 10-15 minutes prior to collection

why can blood with anticoagulant not be used after 15 minutes

the longer the RBC are exposed to anticoagulant the more the artifacts (neutrophils can swell, causes nuclei of WBCs to condense and degenerate to appear pyknotic, or platelets can clump)

common errors when handling blood

1. rapid force

2. spraying the blood through needle

3. water to be present in collection tubes/syringes

4. improper mixing or blood amount

5. overheating/freezing

excessive time at room temp between collection and analysis...

causes autolysis of cells

how many ml can be safely removed from a healthy dog that is NOT a blood donor

0.5 ml/ kg

1 ml from 5 ib animal

20 ml from 100 ib animal

how many ml can be safely removed from a donor animal

10 ml/kg of body weight (10-15%)

every 4-8 weeks

*as long as they have adequate time between, good nutrition and care to rebuild supply

clinical effects of extreme blood loss & when do signs of shock begin to show

effects: decrease in volume and rate of flow

30% signs of shock

40% death can occur

Rouleaux formation

-arrangment of RBCs in columns or stacks like coins

-MOST COMMON in horses

-artifact of sample handling, delayed time between collection and smear, over refrigeration

agglutination

-antibody coats the RBC surface causing clumps; cells attacking themselves because there is something on surface they do not like

-abnormality

how to differentiate between agglutination and rouleaux

-add a drop of saline to blood

-rouleaux disperses in saline and agglutination clumps and sticks

anisocytosis

variation in size of RBCs due to anemia

macrocytes (macrocytic)

RBCs are larger than normal

*high MCV