Low F-PSA/T-PSA, a condition that is evaluated in a comprehensive manner. If the total PSA is less than 3ng/mL and the F-PSA/T-PSA ratio is low, this condition is not a major problem. If the total PSA is greater than 4ng/mL and the F-PSA/T-PSA is low, the possibility of prostate cancer should be highly suspected, and a ratio of less than 17% should be suspected of prostate cancer. You should do prostate finger examination, prostate ultrasound and prostate MRI to rule out the presence of low signal in the peripheral zone of the prostate, and you may have to do prostate puncture if necessary.