Clotting tests

Question 1

Prothrombin time (PT);
Tests the ? pathway, by addition of a tissue factor substitute to the
patient’s plasma.
It is prolonged in ? disease, or if the patient is on ?.

Answer 1

extrinsic
liver
warfarin

Question 2

International normalised ratio (INR);

Ratio of patient’s ? to a normal ? whilst using an international reference preparation (standardises laboratories worldwide).
?-? is the normal range.
Used for ? dosing

Answer 2

PT
control
0.9-1.1
warfarin

Question 3

Activated partial thromboplastin time (APTT);

Addition of a surface activator to the plasma
Tests the ? (contact) pathway.
It is the monitoring required for ? ?(not required for ????).

Answer 3

intrinsic
unfractionated
heparin
LMWH

Question 4

Thrombin time;

Addition of ? to the patient’s plasma.
Prolonged with ? deficiency or abnormal function, or inhibitors such as ?.

Answer 4

thrombin
fibrinogen
heparin