Within the field of erythropoietin (EPO) gene therapy a multitude of in vivo and ex vivo gene transfer studies have been conducted, using viral- and non-viral vector systems. Currently, none of the EPO gene transfer techniques warrants both, efficient and safe application. Hence, it seems to be unlikely that EPO gene doping could be used in a systematic way to enhance sports performance. Nevertheless, it cannot be excluded that people will try to gain benefits from a technology although it has not been yet proven to be successful or safe.

To prevent athletes and trainers from using gene transfer technology a sensitive, reliable, and long-term detectability is a major prerequisite. A number of different EPO gene doping detection strategies have been suggested including indirect detection approaches such as screening for specific blood parameters, or the blood transcriptome. Furthermore, direct detection approaches were conducted including the detection of transgenic protein or transgenic DNA (tDNA).

Currently, most investigators are following the strategy to detect tDNA via real-time PCR assays. The high sensitivity of this detection approach warrants long term detectability following a singlein vivogene doping event and its applicability has been tested in a non-human primate model system. Due to high sensitivity, specificity, and reliability, the PCR-based detection approaches could find application as a standardized doping test. Moreover, tDNA based detection by PCR has already been established for a number of other possible gene doping candidates apart from EPO.