Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios

Recent studies show that spermatozoal DNA integrity is essential for normal fertilization and transmission of paternal genetic information to the offspring. Additionally, fertilization and embryo development depend on the sperm DNA structure (1,2). Generally, while fertile men have high levels of sperm with intact DNA structure associated with normal semen parameters, infertile men have decreased DNA integrity usually associated with abnormal semen parameters (3,4). However, this association is not unequivocal, as there have been several studies indicating that increased sperm DNA damage can occur in men with conventional sperm parameters within normal reference ranges (3,5,6). Increased sperm DNA damage is defined as the percentage by which the number of cells with defects in protamination of DNA structure in the evaluated sperm cells is calculated and expressed as the sperm DNA fragmentation index (DFI) (3). It is generally accepted that there is a significant negative correlation particularly between the abnormal sperm morphology percentage and DFI (3,6). In the present study, the authors evaluated the diagnostic importance and the clinical significance of sperm DFI tests in infertile males with different clinical conditions (7).