Putting the @ symbol before the person's username tags them so that they know they've been mentioned in a post. If it's their original post, you don't need to do it but for me it's easier just to go with the one thing as I'm less likely to stuff up. If you click on a person's username, you will get their profile page, eg. if you click on mine, you will see info about me including what I have put up regarding my cancer experience. To add to any threads, just type in the box and hit "post comment" using the @username if you want to tag someone in particular.
Am I as clear as mud??
I have to say that I'm finding it very bizarre that doctors aren't providing basic information about the test results. I know there was some information that I didn't find out until after rads but I suspect that was more because of the diagnosis fog than anything else as my team were always pretty open about things. You may have to request that your GP is advised of all results as they won't necessarily be. My onc was happy to do this but said that they don't do it as a matter of course because often GPs are rather alarmed at some of the blood levels, etc. during chemo.