I know this sounds strange, but I had a heart attack because of clot last year because my doctor told me I was immune to Plavix, so switched to Effient 7 months ago, and have had easy bruising since except in the last month. There has been no bruising. I hit myself pretty hard twice while working, and normally would have a dark bruise because of the Effient. There is none. The doctor told me that you could not do any tests to see if the drugs work or not. So I have trusted the bruising and bleeding easily (sad to say). Now that it has stopped, I am a bit worried because after Plavix, I had to have 2 more stents put in, because I had the heart attack exactly 1 yr and 1 month after the first. They said the tissue of the artery grew together through the stent because I was immune to Plavix. So I am concerned that there is no more bruising. Anyone know about this kind of thing? Thanks.