Intra-individual variation of the sperm chromatin structure assay DNA fragmentation index in men from infertile couples.
BACKGROUNDThe sperm chromatin structure assay (SCSA) is a valuable tool for prediction of fertility in vivo, with DNA fragmentation index (DFI) of 30% as a clinically useful cut-off level. Previous studies on fertile men have shown a high level of repeatability, with an intra-individual variability in DFI of ∼10%. However, conflicting data on how much the DFI fluctuates within individuals exist. T