Aim: To investigate transfusion transmitted virus (TTV) infection in various populations and its clinical significance. Methods: A nested polymerase chain reaction (PCR) assay with primers from ORF1 of TTV genome was established and it was used to detect TTV DNA in the serum samples from various populations. The patients with TTV DNA positive or not were comparatively and clinically observed. Results: TTV DNA was detected in the sera from 2 of 29 (6.9%) general individuals, 1 of 27 (3.7%) professional blood...