Background: TT virus (TTV) infection is highly prevalent in the general population and in the patients infected with hepatitis B virus (HBV) or hepatitis C virus (HCV). The aim of the present study was to assess the positive rates of TTV DNA using different PCR primer sets in healthy and HBV or HCV-infected individuals in Korea. 

Methods: TTV DNA was investigated in serum samples of 69 healthy individuals and 59 HBV-infected and 34 HCV-infected individuals by nested PCR assays using primers from N22 region, 5′-untranslated region (UTR), and 3′ UTR of viral genome. 

Results: TTV DNA was detected in 43% of total study populations using N22 primers, in 69% using 5′ UTR primers and, in 64% using 3′ UTR primers. No significant difference was observed in the positive rates of TTV DNA between healthy and HBV or HCV- infected individuals. 

Conclusion: The PCR assays for TTV DNA using 5′ UTR primers and 3′ UTR primers exhibited higher positive rates than that of the assay using N22 primers without any significant difference between healthy and HBV or HCV-infected individuals. (Korean J Clin Microbiol 2007;10:14-18)