blood groups

Question 1

hw are blood groups determined

Answer 1

according to antigens expressed on the surface of erythrocytes (generally glycoproteins or glycolipids

Question 2

what are alloantibodies

Answer 2

• specific antibodies directed against erythrocyte antigens (blood types) present in the same species but not in the individual producing the antibody
• extremely important in determining the success or failure of a blood transfusion
• the presence of antibodies directed against RBC antigens will reduce survival of transfused cells (= transfusion reaction)
• may have their effect by agglutination and/or hemolysis of RBCs
• can occur naturally or can be acquired by exposure to the blood group antigen

Question 3

how are blood group systems classified in dogs

Answer 3

dogs have a number of different blood types but pen side tests (snap test/cards) only test if the dog is blood type DEA1.1 (dog erythrocyte antigen)

Question 4

how are blood group systems classified in cats

Answer 4

• cats have 3 different blood groups: A, B and rarely AB
• highly immunogenic
• prevalence of blood groups varies between countries and with breed

Question 5

how are blood group systems classified in horses

Answer 5

Question 6

when would you perform a blood transfusion

Answer 6

• clinical condition of the patient (anemia patient with signs of cardiovascular compromise like tachycardia, tachypnoea, collapse)
• OR PCV <10%
• OR PCV has fallen rapidly to <20% in dogs <15% in cats
• OR during surgery if there is major hemorrhage

Question 7

how do you calculate how much blood to transfuse

Answer 7

1. rule of thumb: 2 ml whole blood/kg of body weight raises PCV by 1%
2. calculation based on donor PCV: (image for calc)
3. dose rate: 1-4 ml/kg/hr

Question 8

why is transfusion useful

Answer 8

rarely a cure –> provides support while an underlying cause is could +/- treatment started
aim is for clinical improvement rahter than obtaining a normal PCV. post transfusion PCV of 25-30% in dogs and 20% in cats`

Question 9

in dogs, the blood type snap test card determines

Answer 9

if blood group is DEA1.1 or not

Question 10

in cats the blood type snap test determines

Answer 10

all blood types of that species

Question 11

blood typing is essential for

Answer 11

all blood transfusions in cats

Question 12

blood cross matching is recommended prior to transfusion for

Answer 12

dogs that had a previous blood transfusion

Question 13

what is the criteria for blood donors

Answer 13

• between 1 and 8 years old
• healthy, not on any medication
• good PCV
• fully vaccinated and wormed
• good temperament
• never had a blood transfusion
• never travelled abroad
• collection of less than or equal to 10% of total blood volume to ensure no adverse effect
• collection of less than or equal to 20 % of total blood volume should not result in clinically significant anemia provided to donor has a normal PCV at collection (can produce hypovolemia in the short term)
• PCV > 35%

incats: (~66 ml blood/kg)
- over 4.5 kg
- must test negative for FIV and FelV
- female donors should have had no previous pregnancies and should be neutered
- 40-50ml collected
- blood group known

in dogs (~90 ml blood/kg)
- over 25 kg
- ~450 ml collected at pet blood bank
- ideally DEA1.1 negative

Question 14

what is Patch’s blood group

Answer 14

AB

Question 15

what is tigger’s blood type

Answer 15

B

Question 16

what is the PCV of a normal dog

Answer 16

25-45%

Question 17

what is the test result and what does it tell you about rio’s blood group

Answer 17

rio has blood group DEA1.1. test result is DEA1.1 positive

Question 18

what is the best route for administration for blood transfusion?
A. peripheral vein (i.e. cephalic)
B. central veing (i.e. jugular)
C. intra osseous route

Answer 18

all three

Question 19

rio has had a previous blood transfusion before with no issues. does this make a transfusion reaction more of less likely

Answer 19

more likely because most problems arise after the 1st transfusion if antibodies have been formed in response to it and 2nd transfusion is of the same blood group (allo-antibodies)

Question 20

do transfused erythrocytes have a longer, shorter or the same lifespan as the body’s own

Answer 20

shorter

Question 21

how does the regeneration of red blood cells impact the blood profile over the first week

Answer 21

• macrocytic
• hypochromic
• regenerative

Question 22

which element of the clotting cascade is affected with anticoagulant redenticides

Answer 22

vitamin K

Question 23

which hemostasis pathways are affected when clotting factors are depleted due to vitamin K deficiency

Answer 23

• extrinsic
• intrinsic
• common

Question 24

the integrity of which pathways does prothrombin time measure

Answer 24

extrinsic and common pathways

Question 25

for prothrombin time, if henry has consumed redenticide, what do you expect to see

Answer 25

prolonged

Question 26

the integrity of which pathways does activated partial thromboplastin time measure

Answer 26

intrinsic and common pathways

Question 27

for activated partial thromboplastin time (time taken to clot), if henry consumed rodenticide, what would you expect to see

Answer 27

prolonged

Question 28

based on the below hematology tests, what type of anemia does henry have

Answer 28

macrocytic, hypochromic regenerative

Question 29

you have 500 ml of blood availible for transfusion. a a general rule of thumb, blood can be transfused at a rate of 5-10 ml per kg per hour. henry weighs 30.5 kg. calculate the flow rate you have to set your infusion pump at for a transfusion of 10 ml per kg per hour. how many hours will it take to transfuse 500 ml

Answer 29

flow rate: 305 ml/hr total time: 98 min or 1 hr. 38 min (10ml/kg)x30.5 kg = 305 ml/hr (500 ml/1)x(1hr/305ml) = 1.64 hr x 60 = 98 min