I don't know whether you, or anybody else participating in this thread, understands exactly what is meant by 48 hours prior to boarding, but if I get my test done at 0900 on Wednesday in Ottawa and board at 1200 on Friday in Civitavecchia (a six hour time difference), am I still OK? Maybe I should ask my test facility to date/time stamp my test in GMT (a four hour difference, but good enough).