After obtaining written informed consent, patients of clinically diagnosed with bilateral CTS were randomized into intervention and control side. Intervention group received one-dose ultrasound-guided PRP injection and control group received one-dose ultrasound-guided normal saline injection. No additional treatment after injection through the study period. The primary outcome is visual analog scale (VAS) and secondary outcomes include Boston Carpal Tunnel Syndrome Questionnaire (BCTQ), cross-sectional area (CSA) of the median nerve, sensory nerve conduction velocity of the median nerve, and finger pinch strength. The evaluation was performed pretreatment as well as on the 2nd week, 1st, 3rd, 6th month and one year after the treatment.