Indeed. The first blood screening technology to test directly for HIV and other viruses (previously, blood screening used human antibody tests which are not entirely reliable) was approved by the FDA last month. This will greatly increase the safety of the blood supply by detecting viruses in blood before there is even an immune response (the technology sniffs out viral RNA/DNA that is integral to the virus itself).
It doesn't work well for the same reason that there isn't a vaccine for HIV. The virus is not free in the blood stream long enough to be detected. It appears to make its way directly into the macrophages once in the bloodstream. The binding sites on the virus that we use to detect it haven't changed since we launched the original test.