Coagulation screen

Question 1

PT measures what pathways?

Answer 1

Extrinsic (Factor 7) pathway and common pathway (factor X, V, II)

Question 2

What can cause an abnormal prothrombin time?

Answer 2

Liver disease, DIC, vitamin K deficiency and warfarin

Question 3

What pathways are measured by APTT?

Answer 3

Intrinsic (factors 8, 9, 11, 12) and common pathway (factors 10 5 and 2)

Question 4

What can cause an abnormal APTT?

Answer 4

Haemophilia A - Factor 8 (X-linked recessive)
Haemophilia B - Factor 9 (X-linked recessive)
Haemophilia C - Factor 11 (autosomal dominant)
Von willibrand disease - Low vWFand low factor 8

Question 5

What are the coagulation results for DIC

Answer 5

PT - Prolonged
APTT - Prolonged
Bleeding time - Increased
Platelets - reduced
(give platelets and correct underlying cause)

Question 6

What are the coagulation results for ITP, TTP or HUS?

Answer 6

Normal PT and APTT. Reduced platelets and increased bleeding time. DO NOT give platelets