Dear Dr, thanks for your help on this website. I suffer from anxiety and am currently receiving medication but something is on my mind which I think could be solved if I knew what size of a cut I would need to get for a blood transmission. I know that exposure to HIV (and other bloodborne diseases) is theoretical via things like razors. If I had gotten a bad cut from a razor would this change things? Or would it not really be possible to get the kind of injury required for HIV transmission, via a razor, as it can't puncture you? Sometimes I manage to cut myself around the ankle and it can be a rather bad slice, which is why I wonder if this type of injury is deep enough. I ask this because I once shared a room with my cousin who mentioned she suspected a couple of guys she dated where gay. I just worried if I had left my razor around she may have used it, and there was not much time after her until I used it. However I gathered that even if the HIV (or other diseases) hadn't died in the time between users, the amount of blood carried on a razor would still not be enough for transmission anyway? I'm guessing that this holds for other things like toothbrushes. I once had a cut on my arm from a razor, and remember at some point my friend was resting on my arm and rubbing his face a bit, I had thought later if he had a nose bleed,and through 'nuzzling' my arm had opened my cut, I'm guessing the amount of blood that would have to be transferred would have to be a lot, so much that I would notice it coming on my arm. I was also in a mosque in Egypt (where there is a lot of hepatitis) and I felt something stick into my foot - it seemed like a splinter, or very fine bit of metal, my friend said it was something from the carpet and it was quite flimsy, but it didn't penetrate my foot deeply or anything and I pulled it out quite easily. I heard from a Dr there I shouldn't worry about blood borne diseases from this, I'm guessing because it didn't penetrate deeply.