Hi there,
1. HIV is diagnosed through a blood test, not through signs and symptoms.
2. One can go for a HIV test 1 month after exposure and retest at the 3rd month for a conclusive result; regardless of whatever symptoms.
From what I've read, seroconversion and ARS are typically synonomous (sometimes ARS is referred to as seroconversion sickness.) According to docs PCR tests will indicate positive during true ARS. I'm not sure about antibody test but a pos certainly wouldn't be far behind. A negative result I would think would be a strong indicator against ARS.
99.9999999% of the "symptoms" that ppl think they are experiencing...are NOT ars related at all. it's in their head!