is brown spotting normal??

i did call earlier today. all they said was come back in monday for another blood test to make sure my levels are still rising right. but i just had a blood test done tuesday. When i asked what it might be they just said old blood never did answer my qestion on if it was normal or not. 

At four weeks along, you're only two weeks past egg implantation. So, it is highly likely that it is just some old blood that is from the implantation. Keep an eye on it. Make sure the amount of spotting doesn't increase much, and make sure it doesn't turn into bright red blood. Generally, brown spotting is nothing to worry about. But, if it continues for a week or more, it could be a sign of a problem. For now, don't worry and just make note of any changes.