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Platelet Function
STEP Study Cards for Platelet Function
Question | Answer |
---|---|
Platelets are activated by- | collagen, thrombin, adp receptors (p2y1 & p2y12) expressed on platelets |
Where are collagen, thrombin, and adp (p2y1&p2y12) expressed- | on platelets |
Platelets are also known as- | thrombocytes |
Platelets potentially modulate inflammatory processes by- | intercepting w/ leukocytes & secreting cytokines and chemokines |
What helps to reinforce the platelet plug- | high concentration of myosin & actin |
Normal platelet count for healthy adult- | 150,000-400,000 per mm of blood |
The formation of fibrin strands woven through the plug & cross-linked to form a ___ ___ - | fibrin net |
T or F The discovery of platelet dysfunction in a pt may not always be associated w/venous injury | true |
Suggested indications for platelet function testing include the following: Pt who experiences easy bruising Women experiencing a menorrhgia (heavy menstrual bleeding) - - - | pre-op assessment anti-platelet therapy monitoring uremia (circulating substances impair platelet interactions w/the vessel wall) cirrhosis (thrombocytopenia, coagulopathy, & vascular abnormality) |
What test was used to evaluate platelet function by making a standard incision on the forearm & measuring the time required for bleeding to stop_ | bleeding time test |
Why is BT being phased out of hospitals today- | not sensitive or specific, doesn't reflect the risk or potential severity of a surgical bleed, rarely reproducable, easily affected by ingestion of aspirin or other meds leaves a small scar |
Microprocessor controlled instrumentation & disposable test cartridges use what blood sample- | whole citrated blood obtained from a single venipuncture |
T or F Improved diagnostic value, PT acceptance & cost are reason enough to evaluate platelet function on new instrumentation over the use of the BT test | true |
What was the first analyzer commercially available in-vitro test to measure platelet function | PFA-100 |
How much blood does the PFA-100 require | 800microliters of whole citrated blood |
CT means | closure time |
What does closure time mean | the time taken to occlude the flow |
What is the primary test cartridge used to id mild to severe platelet dysfunction, von Willebrand factor deficiency or the effect of aspirin | the collagen-epinephrine cartridge |
What does the VerifyNow Test, test for | GPIIb/GPIIIa dependent aggregation aspirin effects P2y12 blockade |