Platelet Lab Tests Flashcards
How do you do a template bleeding time?
Inflate blood pressure cuff, make incision, time how long it takes to stop bleeding
What does template bleeding time measure?
PLATELETS. Not coagulation factor
What does a closure time test do?
Measures how quickly platelets occlude small holes in a membrane.
When is closure time better used than template bleeding time?
Aspirin related bleeding, vW disease
How do you do a platelet aggregation test?
Take patient sample, add aggregating agents, see if they aggregate
What do you measure in the platelet aggregation test?
DECREASE in sample turbidity.
Why do you use the platelet aggregation test?
Find platelet function abnormalities
What is the general structure of coagulation tests?
Take cells into citrate tube (prevents clotting)
Spin tube down and decant plasma
Add reagents to plasma
Watch for fibrin formation
What are added together to measure prothrombin time?
Plasma and thromboplastin, which acts just like Tissue factor
What is prothrombin time used to measure?
Extrinsic pathway
When would you find PT increased?
Decreased VII, X, V, II, I
Coumadin
Heparin
DIC
What is an INR?
Corrected PT
What is the main test used for coumadin monitering?
INR
How do you do the partial thromboplastin time?
Take plasma and add phospholipid
What does partial thromboplastin time measure?
Intrinsic pathway
