Cross Species - Coagulation Panels & Blood Transfusions

Question 1

what is primary hemostasis?

Answer 1

formation of the platelet plug

Question 2

what test evaluates platelet function? when is it done? what is a normal value?

Answer 2

BMBT - only done if platelet count is normal, normal is under 4 minutes

Question 3

what are some examples of how platelet abnormalities manifest as clinical signs?

Answer 3

mucosal bleeding, epistaxis, scleral hemorrhage, gi bleeding, gingival bleeding, petechiation, & ecchymoses

Question 4

what are some common diseases that cause platelet abnormalities?

Answer 4

canine ITP, VW disease (most common inherited bleeding disorder in dogs)

Question 5

what is secondary hemostasis? what pathways are involved?

Answer 5

formation of fibrin clot via coagulation factors - extrinsic, intrinsic, & common

Question 6

what factors are included in the extrinsic pathway? what testing is involved in this pathway?

Answer 6

factor VII & tissue factor - prothrombin time, PT

Question 7

what factors are included in the intrinsic pathway? what testing is involved in this pathway?

Answer 7

factors XI, IX, XII, VIII - activated partial thromboplastin time, PTT

Question 8

what factors are involved in the common pathway? what testing is involed in this pathway?

Answer 8

factors II, X, VIII, V, fibrinogen - tests aPTT & PT

Question 9

what factors are vitamin k dependent?

Answer 9

II, VII, IX, & X

Question 10

what is ACT? what does it assess?

Answer 10

activated coagulation time - assess all pathways but less sensitive & more subjective

Question 11

what are some reasons you may have abnormal results due to spurious error?

Answer 11

traumatic blood draw or underfilled tube

Question 12

what testing is most often done to get the most complete picture when assessing coagulation? what is it performed on?

Answer 12

typically run PT & aPTT together

Question 13

what are some common causes of hemoabdomen/hemothorax?

Answer 13

anticoagulant rodenticide toxicosis, congenital factor VIII deficiency (hemophilia a), & hepatic failure

Question 14

why is PT prolonged prior to aPTT in rodenticide toxicity?

Answer 14

factor VII has the shortest half life of the vitamin k dependent factors, so it is depleted first

Question 15

what is fibrinolysis? what proteins are involved?

Answer 15

clot breakdown - tissue plasminogen activator & plasminogen

Question 16

what testing can be done to assess fibrinolysis?

Answer 16

fibrin-degredation products, d-dimers, & thromboelastography - provides global assessment of blood clotting abnormalities

Question 17

what are some diseases that can cause pathologic thrombosis in small companion animals? why?

Answer 17

PLN in dogs, early stages of DIC, colic, & laminitis in horses - pathologic thrombosis occurs due to loss of anticoagulant factors or an excess of procoagulant factors

Question 18

what determines blood type?

Answer 18

specific antigens on red blood cell surface - antigen & typing are species specific

Question 19

what are the two types of antibodies to red blood cell antigens?

Answer 19

naturally occuring - present in blood without prior transfusion exposure & acquired - following RBC antigen exposure

Question 20

what are the major blood types in dogs? what do you commonly test them for?

Answer 20

DEA types 1-8 - test for DEA 1.1 positive or negative

Question 21

what blood type in dogs is the universal donor? how does this work for first time transfusions?

Answer 21

DEA 1.1 negative are universal donors - suitable for DEA 1.1 negative & positive - yes even for first time

Question 22

when may an acute hemolytic reaction be seen in a dog receiving a blood transfusion? why?

Answer 22

can occur in DEA 1.1 negative if dog was sensitized by previous transfusion - naturally occuring antibodies to RBC antigen does not exist, so cross match is not required before the first transfusion but must be done prior to all subsequent transfusions

Question 23

what blood typing is used in cats? which is more common?

Answer 23

AB system - most are type A

Question 24

what cats are typically type b?

Answer 24

purebred cats - devon rex, cornish rex, bristish shorthairs

Question 25

why is cross matching & blood typing in cats necessary? even at first time transfusion?

Answer 25

other RBC antigens & naturally occuring antibodies are not detected by blood typing!!!!! they have naturally occuring antibodies to the other blood type antigen

Question 26

T/F: never give type a blood to a type b cat

Answer 26

TRUE

Question 27

is there a universal blood donor type in cats?

Answer 27

no - but type AB cats can receive type A or B blood because they don’t have antibodies to either type but they are rare

Question 28

when can neonatal isoerythrolysis occur in cats?

Answer 28

if type A or type AB kittens are born to a B queen mated to a type A tom

Question 29

what are the equine blood types?

Answer 29

7 recognized types - A, C, D, K, P, Q, & U

Question 30

what blood types are most important for neonatal isoerythrolysis & hemolytic transfusion reactions in horses?

Answer 30

Aa & Qa

Question 31

why are first transfusions without cross matching in horses usually safe?

Answer 31

less than 10% of horses have naturally occuring alloantibodies

Question 32

how many blood groups do cattle have? why is matching difficult?

Answer 32

11 major groups - b group has multiple antigens making close matching of donor & recipient difficult

Question 33

T/F: neonatal isoerythrolysis doesn’t occur naturally in cattle

Answer 33

TRUE

Question 34

how many blood groups do sheep have? goats?

Answer 34

sheep - 7, goats - 5

Question 35

T/F: some cattle vaccines may contain RBC antigens and can cause antibody formation without a blood transfusion

Answer 35

TRUE

Question 36

when is cross-matching usually done?

Answer 36

done after typing in dogs & cats to determine blood transfusion compatibility

Question 37

what are the two types of cross matching? which is most important? why?

Answer 37

major - donor RBC + recipient serum to determine if the recipient has preformed antibodies to donor RBC antigens & minor cross match where the donor serum + recipient RBC to determine if donor has preformed antibodies to recipient RBC antigen

Question 38

when is a cross match performed in cats?

Answer 38

before the first & every subsequent transfusion because they have naturally occuring antibodies

Question 39

when is a cross match done in all other species?

Answer 39

after the first & every subsequent transfusion because antibodies are induced by exposure to foreign RBC

Question 40

how is a major cross match performed?

Answer 40

wash RBC 3 times to remove substances that can cause agglutination, mix RBC with serum & assess for agglutination

Question 41

microscopic or macroscopic agglutination & macroscopic hemolysis particularly in horses indicates what?

Answer 41

incompatible transfusion

Question 42

when is a minor cross match performed?

Answer 42

only done in small animal patients receiving significant volume of plasma - donor antibodies to recipient RBC antigen are usually diluted enough to not be of significant concern

Question 43

what is a mare-foal, mare-stallion incompatibility test?

Answer 43

cross match done to assess incompatibility to determine risk of neonatal isoerythrolysis - assess antibodies in mare serum to RBC antigen of the foal or stallion