Zika antibodies (particularly IgG) can persist for months or years, so testing 6 months later can still detect past infection. However, interpreting results gets trickier the longer you wait. IgM antibodies (which indicate recent infection) may have waned, leaving only IgG (which could mean infection happened months ago). If you’ve already waited 6 months and have no pregnancy plans for another few months, testing might not change your decisions.