90 days/3 months is just the official standard. Infections are picked up long before then.
Even if just the finger prink antibody 2nd generation test? How come the clinic workers still stick with 90 days? I don't understand. Why they make people unnecessarily worried if 8 weeks is conclusive?
Yes, any test at 8 week is conclusive. You do not need to retest at 12 weeks.