5-30 KRAFTS Hemostasis

Question 1

What is Template Bleeding Time?

Answer 1

Tests ONLY the platelet response (no cascade of factors) by making incision and timing how long to stop bleeding

Question 2

What is Platelet Aggregation test?

Answer 2

Add aggregating agents to patients’ sample

Measure platelets aggregation

Question 3

How does the Prothrombin Time (PT) test work?

Answer 3

THROMBOPLASTIN added to Plasma
Observe time to clot
Measures EXtrinsic pathway

Question 4

What is thromboplastin?

Answer 4

Tissue Factor + phospholipid

Question 5

What can -> ↑PT?

Answer 5

↓VII, X, V, II, I
Coumadin (obviously, decreases factors)
Heparin (stimulates ATIII -> ↓factors)
DIC (↓coag factors)

Question 6

Which Factor has the shortest half-life?

Answer 6

Factor VII

Question 7

What’s an INR?

Answer 7

International Normalized Ratio
Just a corrected PT
Normalizes PT across different manufacturers
B/c different thromboplastins from different companies could lead to different PT’s

Question 8

What does “Partial Thromboplastin” refer to?

Answer 8

Recall Thromboplastin = TF + phospholipid

“Partial” refers to phospholipid which is necessary for intrinsic cascade

Question 9

What can -> ↑PTT?

Answer 9

Hemophilia A (Factor VIII deficiency)
	Hemophilia B (Factor IX deficiency)
	DIC (↓coag factors)
	Heparin (stimulates ATIII -> ↓factors)
	Inhibitors (Ab’s that bind phospholipids in body)

Question 10

How does PTT work?

Answer 10

Add Partial Thromboplastin + Plasma
Measure time to clot
Measures intrinsic pathway

Question 11

What is Thrombin Time (TT)?

Answer 11

Add Thrombin + Plasma
Observe time to clot
Measures fibrinogen -> fibrin conversion

Question 12

What can ->↑TT?

Answer 12

↓Fibrinogen

↑FDPs (negative feedback)

Question 13

When would you order a TT?

Answer 13

To rule out fibrinogen problem (rare)

Question 14

What is a PTT Mixing Study?

Answer 14

PTT is ↑
Add pooled plasma from hundreds of different people
If PTT corrects: Something’s missing from patient’s plasma (eg Factor VII)
If PTT doesn’t correct: Inhibitors (Ab’s) are present in patient’s plasma

Question 15

What is Fibrin Degradation Product Assay?

Answer 15

Measures FDPs (including D-dimers)
	VERY sensitive (SNOUT: sensitivity rules out)

Question 16

What is FDP assay used for?

Answer 16

Rules out clot (b/c if there’s a clot ANYWHERE, this test will pick it up)

Question 17

What could cause ↑FDPs?

Answer 17

Thrombi
Any minor clotting (b/c recall that clots are also being broken down as
quickly as they are built up)

Question 18

What does Fibrinogen assay do? When would you use it?

Answer 18

Measures level of fibrinogen.

Used to Dx DIC and follow patient w/ massive bleed

Question 19

What would cause ↓Fibrinogen?

Answer 19

Massive bleed

DIC

Question 20

What test would you use to monitor Warfarin therapy?

Answer 20

INR

Question 21

What test would you use to monitor Heparin therapy?

Answer 21

PTT