NAT test presents high sensibility of nucleic acid detection, contributing to a significant increase in the transfusional safety, since the nucleic acid amplification test (NAT) for HIV and HCV detection of blood donors samples provides an important complement to the traditional serological tests (that researches antibodies and antigens) reducing the “immunological window” from 22 to 11 days for HIV and from 70 to 12 days for HCV.