Can rpr test for syphilis give false negative?if syphilis is highly suspected should i retest for it ?

The false: Negative rate is low though i can't quote it. I would retest if for nothing other than to ease your mind. Good luck but i bet u don't have it.

Prozone effect: False (-) in RPR syphilis testing occurs when there is a prozone effect. Why? It's because the concentration of syphilis antibodies is so high, it interferes with the antigen-antibody interactions that result in a (+) reaction. A false (-) result can also occur during primary syphilis since not enough time has passed to allow high enough antibody levels for a (+) reaction to occur.