Coagulation panel

Question 1

aterial thrombosis

Answer 1

• platelet rich + white.
• caused by atherosclerosis and endothelium damage
• adheres to vessel walls

Question 2

venous thrombosis

Answer 2

• rbc rich + red
• loosely attached

Question 3

what’s added to tube when measuring coagulation factors to stop clotting

Answer 3

citrate

Question 4

what does PT measure

Answer 4

time taken to clot in extrinsic and common pathways

Question 5

what does APTT measure

Answer 5

time taken to clot in intrinsic and common pathways

Question 6

what does INR measure

Answer 6

ratio of normal PT compared to patient PT therefore ideal INR is ~1.
only technically valid for warfarin.

Question 7

what triggers intrinsic pathway

Answer 7

contact factor

Question 8

what triggers extrinsic pathway

Answer 8

tissue factor

Question 9

what is a DOAC

Answer 9

direct acting oral anticoagulant

Question 10

which DOACs inhibit factor X

Answer 10

rivaroXaban, edoXaban, apiXaban

Question 11

which DOAC inhibits factor II

Answer 11

Dabigatran (anti-thrombin)

Question 12

How do DOACs affect coag panel tests

Answer 12

variable non-linear impact on PT and APTT

Question 13

what are DOACs used for

Answer 13

stroke prevention, DVT, pulmonary embolism

Question 14

what cofactor does synthesis of IX, X, II, and VII require

Answer 14

vitamin K

Question 15

what is warfarin

Answer 15

a vitamin K antagonist therefore anticoagulant

Question 16

what coag panel tests does warfarin affect

Answer 16

prolongs PT and APTT
PT is particularly sensitive to it.
INR used to adjust dose

Question 17

what are heparins

Answer 17

sulphated glycosaminoglycans.

Question 18

how do heparins inhibit coagulation

Answer 18

• indirectly by increasing anticoagulant power of antithrombin
• mainly affects factors IIa and Xa

Question 19

how is unfractionated heparin delivered

Answer 19

intravenously with loading dose before continuous infusion.
needs careful monitoring
binds to antithrombin and thrombin

Question 20

how is low molecular weight heparin delivered

Answer 20

subcut injection
only binds to antithrombin which acts on factor Xa

Question 21

how does heparin affect coag panel test

Answer 21

affects APTT

Question 22

what do thrombolytic drugs target

Answer 22

plasminogen e.g. tPA

Question 23

primary prevention using anti platelets

Answer 23

if high cardiovascular risk score

Question 24

secondary prevention using anti platelets

Answer 24

after MI, stroke, stent, PVD

Question 25

2 examples of anti-platelets

Answer 25

aspirin and clopidogrel

Question 26

Haemophilia A

Answer 26

makes no or little factor VIII increases APTT

Question 27

Haemophilia B

Answer 27

makes no or little factor IX increases APTT

Question 28

what does Von Willebrand factor do

Answer 28

- binds platelets and exposed endothelium. - carrier for FVIII

Question 29

Quantitative Von Willebrand disease

Answer 29

low levels of Von Willebrand factor

Question 30

qualitative Von Willebrand disease

Answer 30

abnormal function of Von Willebrand factor

Question 31

how might VWD be detected on coag panel

Answer 31

prolonged APTT as less FVIII

Question 32

symptoms of VWD

Answer 32

easy bruising, mucosal bleeding

Question 33

disseminated intravascular coagulopathy (DIC)

Answer 33

- normal haemostasis not regulated properly - coagulation activated and fibrin deposit so thrombi form - causes clotting factors and platelets to run out so then start bleeding a lot.