With a low positive it may be a false pos but I'd wait atleast the 12 to 16 weeks before doing the western blot. I actually did it a few times. I only say wait because you'll wonder if it was a false neg, like me I ended up doing it again at 1 year mark and had the same neg result. Basically the recommend to wait 12 weeks. Best of luck to you. When was the last time u tested for a base line test before that low pos.