(APTT)/(TT) TEST

Question 1

coagulation test used to monitor low-dose heparin therapy and to screen for function of the intrinsic and common pathways of hemostasis

Answer 1

APTT

Question 2

Lipid portion of tissue thromboplastin, is the reagent used in performing the APTT.

Answer 2

Partial Thromboplastin

Question 3

Manufactured from rabbit or bovine brain tissue as well as from vegetable sources such as soybeans.

Answer 3

PTT Reagent

Question 4

Perform the function of platelet factor 3 (PF3) in the APTT test.

Answer 4

PTT Reagent

Question 5

PTT Reagent Contains activators such as:

Answer 5

Kaolin or silica to activate the contact factors in the intrinsic pathway

Question 6

second reagent used in the test and is added to supply the ionized calcium required to activate prothrombin in the common pathway.

Answer 6

Calcium chloride (CaCl2)

Question 7

Principle of APTT

Answer 7

✓ XII → XI → IX:VIII → X:V → II → i
✓ Performed by combining citrated patient plasma with two reagents: partial thromboplastin and calcium chloride (CaCl2)
✓ Pre-warmed patient plasma is combined with partial thromboplastin and allowed to react → activation of factors in the intrinsic pathways begins (activation that would be initiated by PF3 in vivo)
✓ CaCl2 → added to plasma-partial thromboplastin mixture to allow the reaction necessary for fibrin clot formation.

Question 8

APTT Reference Value:

Answer 8

20 – 35 seconds

Question 9

The thrombin time test determines the rate of thrombin-induce cleavage of fibrinogen to fibrin monomers and the subsequent polymerization of hydrogen-bonded fibrin polymers.

Answer 9

PRINCIPLE OF TT

Question 10

Used to measure the availability of functional fibrinogen

Answer 10

TT Test

Question 11

TT Test are Prolonged in cases of:

Answer 11

✓ Low levels of fibrinogen
✓ Non-function fibrinogen
✓ Presence of heparin | fibrin/fibrinogen products | thrombolytic agents (streptokinase)