Haemostasis lab testing Flashcards
Which anticoagulant is used in coagulation screening tests?
Sodium citrate
What should the ratio of blood to sodium citrate be?
9:1
What does sodium citrate do to the sample?
Removes calcium
List some routine coagulation tests
Prothrombin time
Activated partial prothrombin time
Thrombin time
D-Dimer
Fibrinogen
Platelet count
Which clotting pathway does prothrombin look at?
Extrinsic pathway and common pathway
Which reagent is used in a PT test and what does it contain?
Thromboplastin
Excess amount of calcium, tissue factor and phospholipids to mimic platelets
Which factors does the PT test look at?
II
VII
IX
X
What can prolonged PT results indicate?
Liver disease
Vitamin K deficiency
DIC
Which clotting pathway does the APTT test look at?
Intrinsic pathway and common pathway
What does the APTT reagent contain?
Silica, phospholipids, calcium
What can prolonged APTT results indicate?
DIC
Liver disease
Anticoagulants (heparin)
Factor deficiency
What reagent is added to the TT test and why?
Thrombin added to patient plasma to convert fibrinogen to fibrin
Why is a thrombin time usually performed?
To investigate an unexplained APTT
What can a prolonged TT test indicate?
Hypofibrinogenaemia (low levels of fibrinogen)
Heparin contamination
Dysfibrinogenaemia (irregularity with fibrinogen structure, not converting to fibrin)
What does a reptilase test show?
Normal RT indicated heparin contamination
