MLAB121 - Clotting Factors

Question 1

What is Hemostasis?

Answer 1

Process of stopping blood

Question 2

Platelet activation includes?

Answer 2

Adhesion and aggregation

Question 3

Steps of Platelet Activation

Answer 3

Vaso-constrict

Platelets activated, release granules and change shape

Question 4

Two properties of Platelet activation

Answer 4

Adhesion - sticking to blood vessel wall

Aggregation - sticking together

Question 5

Instrinsic Pathway include which Clotting Factors

Answer 5

Initiated by FXII -> FXI -> IX -> VIII

Question 6

Problems in hemostasis

Answer 6

Insufficient or delayed clotting

Intravascular clotting

Question 7

Hemaphilia A is deficient of?

Answer 7

Factor VIII

Defect of X chromosome

Question 8

Hemaphilia B is deficient of?

Answer 8

Factor IX

Defect of X chromosome

Question 9

Acquired disorders include?

Answer 9

Vit. K Deficiency
Disseminated intravascular coagulation (DIC)
Heparin
Coumadin (wafarin)
Aspirin
Liver disease
Thrombophilia (excessive clotting)

Question 10

Prolonged bleeding time has a low platelet count of?

Answer 10

Less than 50

Question 11

4 QC for Bleeding Time Test

Answer 11

Do not touch incision when blotting blood
Record if patient has used aspirin
Proper PPE
Follow standard precautions

Question 12

What does PT monitor?

Answer 12

Monitor oral anticoagulant therapy (Coumadin)

Question 13

Reagent of thromboplastin?

Answer 13

Tissue factor III-phospholipid and CaCl

Question 14

What factors deteriorate after 10min?

Answer 14

Factor VIII and Factor V

Reagents evaporates

Question 15

Principle of clot detection

Answer 15

Uses viscosity to detect
Increased viscosity if measured through motion of stainless steel ball
Constant pendulum swings ball creates electromagnetic field
Once plasma clots, viscosity of plasma increases, slowing ball down

Question 16

What ISI?

Answer 16

International Sensitivity Index - Specific to thromboplastin

Question 17

Normal Range of PT in seconds?

Answer 17

10-14s

Question 18

Critical Value for PT in seconds?

Answer 18

> 25s

Question 19

Prolonged PT is influenced by?

Answer 19

Alcohol
Hep B
Aspirin

Question 20

Two reagents used in APTT

Answer 20

1. Cephaloplasmin (phospholipid)

2. CaCl2

Question 21

What temperature and time are required for Cephaloplasmin and CaCl2?

Answer 21

5min at 37 degrees

Question 22

Sources of Errors associated with specimen.

Answer 22

Order of draw
Inappropriate ratio of anticoagulant to blood
Clotted, hemolyzed or lipemic samples
<10,000 plaelets 
Delay in testing or processing
Inappropriate storage

Question 23

Normal range for PTT in seconds

Answer 23

25 - 35 seconds

Question 24

Critical value ofr PT in secs?

Answer 24

> 25 seconds

Question 25

Sources of error associated with procedure

Answer 25

Incorrect preparation of reagents Failure to properly store reagents Use of reagents beyond reconstituted stability time or expiration date Contaminated reagents

Question 26

Therapeutic range of PT in seconds?

Answer 26

16 - 18 seconds

Question 27

Therapeutic Range of PT for INR?

Answer 27

2 - 3

Question 28

Factors that require Ca?

Answer 28

XI -> IX -> VIII | and X -> V

Question 29

Sources of errors associated with storage?

Answer 29

Incorrect preparation of reagents Failure to properly store reagents Use of reagents beyond stability time and expiration date Contaminated reagents

Question 30

Therapeutic range of PTT?

Answer 30

1.5 to 2x normal range

Question 31

Critical value for PTT in seconds?

Answer 31

60 - 100 seconds

Question 32

Liver disease, decreased Vit. K, and defective FVII is associated with?

Answer 32

Prolong PT and Normal PTT

Question 33

Decreased or defective FI/II/V or X, severe liver disease, disseminated intravascular coagulation (DIC) - intrinsic system

Answer 33

Prolonged PT and PTT results

Question 34

Defective VII, IX, XI, von Villebrand disease or lupus is present in?

Answer 34

Normal PT and Prolonged PTT

Question 35

Types of POCT tests

Answer 35

Coagulation Cardiac Markers Pregnancy tests Blood gases