Does exposure to infected blood always transmit hiv?

Not Always. Exposure to most body fluids - especially blood & genital fluids - from a person with HIV has the potential to transmit the virus. If you have had an exposure discuss the details of that exposure with an expert - ideally within the first 24 hours. Steps can be taken in the first few days of an exposure to prevent lifelong infection with hiv. Locate a test/treatment site near you at www.Hivtest.Org.
Depends. It will have to do direct body fluid contact and i presume that you are referring to HIV infected blood.