PSA (along with digital rectal exam) remains the usual standard for initial testing despite its flaws . The next step is PSA with %free PSA. Then there are a range of other options. The ones I have in mind based on my own research if my PSA spikes again are 4K score and 3T MP MRI at a facility that specializes in prostate scans.
My PSA spiked as high as 7.2, but %free PSA correlation put me in a low cancer risk category. It since subsided to 3.0, and I;m having ongoing PSA with % free testing every 90 days.