Western Blot accuracy, how long to wait?

I was told by a counselor that western blot can detect HIV 4 days after infection and be very accurate. Is this correct? She said it's extremely sensative, and because of this, it has a high rate for false positives. Therefore it is only used as a confirmatory test.

So my real question is this:

Can you take a western blot test 16 days after the incident and expect a negative result to be accurate? I know western blot tests are only used as confirmatory tests, but let's say you could take it.

[Teak]

You don't get a stand alone Western Blot test. You get an ELISA test first, if it is reactive then your sample will have a Western Blot test ran on it to confirm the positve result. If the Western Blot is Negative, then you are Negative.