HEMOSTATIC TESTS/ DRUG EFFECTS, Circulating inhibitors

Question 1

Normal PT, APTT, TT, Platelet Count indication

Answer 1

Normal hemostasis, platelet function disorder, Factor XIII deficiency, vascular hemostasis disorder, fibrinolysis disorder

Question 2

5M Urea (Duckert’s Test) purpose

Answer 2

Clot stability test for Factor XIII

Question 3

PT prolonged, APTT, TT, Platelet Count normal

Answer 3

Factor VII deficiency

Question 4

PT, TT, Platelet Count normal, APTT prolonged

Answer 4

Factor VIII, IX, XI, XII, Prekallikrein, HMWK deficiency, Von Willebrand’s disease, circulating anticoagulants (e.g., lupus)

Question 5

PT, APTT prolonged, TT, Platelet Count normal

Answer 5

Vitamin K deficiency, oral anticoagulants, Factor V, X, II deficiency

Question 6

PT, APTT, TT prolonged, Platelet Count normal

Answer 6

Heparin (large dose), liver disease, fibrinogen deficiency/disorder

Question 7

PT, TT, APTT normal, Platelet Count low

Answer 7

Thrombocytopenia

Question 8

PT, APTT, TT, Platelet Count low

Answer 8

Disseminated intravascular coagulation (DIC)

Question 9

Penicillin G effect on coagulation

Answer 9

Weakens platelet function, increases bleeding time

Question 10

DDAVP (Desmopressin) effect on coagulation

Answer 10

Increases VIII:C, can shorten APTT

Question 11

Isoniazid (INH) effect on coagulation

Answer 11

Can cause thrombocytopenia, increases bleeding time

Question 12

Aspirin products effect on coagulation

Answer 12

Prolongs bleeding time by inhibiting thromboxane A2

Question 13

Phenothiazines effect on coagulation

Answer 13

Stimulates lupus anticoagulant production, prolongs APTT

Question 14

Phenylbutazone effect on coagulation

Answer 14

Weakens platelet function, enhances warfarin effect, prolongs bleeding time

Question 15

Metronidazole effect on coagulation

Answer 15

Improves warfarin effect, can prolong PT

Question 16

Streptomycin effect on coagulation

Answer 16

Stimulates inhibitors to Factor V, can prolong PT and APTT

Question 17

Acquired inhibitors of coagulation; prolong PT or APTT not corrected by fresh plasma

Answer 17

Circulating Inhibitors (Circulating Anticoagulants)

Question 18

Antibodies against specific coagulation factors; associated with bleeding

Answer 18

Specific Inhibitors

Question 19

Examples of Specific Inhibitors

Answer 19

Antibodies to factors VIII and IX (most common)

Question 20

Directed against phospholipids; generally not associated with bleeding

Answer 20

Lupus Anticoagulant action

Question 21

Non-specific inhibitors

Answer 21

Lupus anticoagulant, paraproteins, fibrinogen degradation products

Question 22

Immunoglobulins associated with Lupus anticoagulant

Answer 22

IgG, IgM, IgA

Question 23

Coagulation results for Lupus anticoagulant

Answer 23

“Normal or slightly increased PT and Increased APTT”

Question 24

Tests for Lupus anticoagulant

Answer 24

Substitution tests, Platelet neutralization test, dRVVT

Question 25

Naturally occurring inhibitors of coagulation

Answer 25

Protein C/Protein S system, Plasma serine protease inhibitor (SERPIN) system

Question 26

Protein C is activated by

Answer 26

thrombin bound to thrombomodulin (TM)

Question 27

Activated Protein C (APC) function

Answer 27

Inactivates Factors Va and VIIIa

Question 28

Protein S function

Answer 28

Co-factor to Protein C

Question 29

Main serine protease inhibitor

Answer 29

Antithrombin (AT)

Question 30

Antithrombin (AT) inhibition targets

Answer 30

IIa (thrombin), IXa, Xa, XIa, kallikrein, XIIa

Question 31

TFPI function

Answer 31

Inhibits VIIa