Lecture 9 - Coagulation testing Flashcards Preview

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Flashcards in Lecture 9 - Coagulation testing Deck (43):
1

what sample is used for most coagulation testing

PLASMA (use a citrate/blue tube)

2

why not use serum

it clots and lacks factors needed for testing

3

4 venipuncture sample tips

1. use plastic syringe and tube
2. fresh, clean stick
3. do not collect from catheter
4. properly fill the tube

4

__ inhibits coagulation by binding calcium

sodium citrate

5

ratio of citrate to blood MUST be __ why need to fill it appropriately

1:9

6

Analysis must be preformed ASAP or

plasma should be frozen within 30mins

7

After centrifugation what is present in citrated plasma

only coagulation factors and other blood chemicals
(NO WBC, RBC, Platelets, or Ca!)

8

7 tests for coagulation/hemostatic function

1. PT
2. PTT
3. ACT
4. Fibrinogen concentration and TT
5. FDPs
6. D-dimers
7. thromboelastography

9

__ coagulation model is not what happens in the body but what happens in the tube, important for understanding tests

classic cascade

10

cats, manatees, dolphins and other exotics lack __

factor 12

11

__ tests the extrinsic (and common) pathway

PT (prothrombin time or one stage prothrombin time) measures time for clot to form when tissue thromboplastin is added = "extrinsic"

12

How does PT test the extrinsic pathway

measures time for fibrin clot to form in citrated plasma after adding tissue factor (thromboplastin), Ca, and substitute for platelet = "extrinsic" bc adding things

13

a __ % deficiency is required before prolognation of PT and PTT

70%

14

prolonged PT means there is inhibition or deficiency of

factor 7, tissue factor or the common pathway factors

15

what factors are vitamin K dependent coagulation factors

2, 7, 9, 10

16

PT can be used to monitor __ therapy

warfarin

17

PT is the best test for __

vitamin K antagonism or deficiency

18

__ and __ test the intrinsic (and common) pathway

PTT (activated Partial Thromboplastin Time) and ACT

19

Which test does NOT have tissue factor/thromboplastin added to tube?

PTT (why it's "intrinsic"). only add things already in the body like contact activator, Ca, and platelet substitute

20

PTT and ACT can be used to monitor __ therapy

heparin

21

artificially prolonged test times can be caused by

1. delayed testing
2. warm sample
3. low plasma citrate ratio (inappropriate filled tube) = erythrocytosis

22

__ test uses patient's own clotting factors, Ca and platelet's, it can be done in the clinic for this reason!

ACT

23

ACT measures time for fibrin clot to form in __ sample using special tube and patient's own factors

WHOLE BLOOD (PT and PTT tests are run using citrated plasma)

24

ACT stands for

activated clotting/coagulation time

25

ACT must be __% deficient before prolongation is detected

95% (compared to 70% for PT and PTT) - Not the best test for this reason, but better than nothing

26

severe __ can prolong ACT results

thrombocytopenia

27

ACT sample needs to be ran at __ temperature

body T (37C)

28

ACT and PTT test the same thing but the __ are different

prolongation detections

29

PT stands for

prothrombin time

30

PTT stands for

activated partial thromboplastin time

31

ACT stands for

activated clotting time

32

TT stands for

thrombin time (qualitative and quantitative fibriongen defects)

33

fibrinogen estimated by heat ppt is better at detecting

elevations than decreases

decrease =
conversion of fibrinogen to fibrin
DIC

Increase =
inflammation

34

Does fibrinogen increase or decrease with DIC

Decrease

35

fibrinogen estimate heat ppt test does NOT detect __ fibrinogen activity, it only estimates fibrinogen quantity

defective

36

__ is a more specific measurement of fibrinogen quantity and activity (not readily available, also don't usually need these specific measurements)

TT (thrombin time) and Thromboelastography

37

role of plasmin in fibrinolysis

breaks fibrinogen/fibrin down into FDPs and D-dimers

38

What are FDPs (or FSPs)

fibrinogen and fibrin degradation products

39

FDPs are formed from Plasmin degradation of

fibrinogen, fibrin monomers, and crosslinked fibrin

40

__ are formed by plasmin degradation of crosslinked fibrin

D-dimers (and FDPs)

41

increased concentration of __ and __ INHIBITS coagulation and promotes bleeding

FDPs and D-dimers

42

__ is increase of FDPs only (seen in envenomations, exess TPA release during shock, heatstroke, sx trauma)

fibrinogenolysis (promotes bleeding)

43

__ from DIC, sepsis/inflammation, internal hemorrhage, or thromboembolic dz will see BOTH D-dimers and FDPs

increased fibrinolysis