Viable sperm DNA fragmentation index (SDF) provides better diagnostic accuracy than total SDF in male infertility: a cross-sectional study

Background: Sperm DNA fragmentation index (SDF) is a key biomarker for male infertility; however, traditional SDF measurements include non-viable sperm, reducing clinical relevance. The viable SDF may provide greater diagnostic accuracy. This study aimed to explore the potential of viable SDF cutoff and assessed its predictive value for male fertility. Methods: This cross-sectional study enrolled men undergoing reproductive evaluation at a tertiary reproductive medical center. Semen analysis followed the World Health Organization (WHO) 5th edition guidelines. Total and viable SDF were measured using the sperm chromatin structure assay, with viability assessed using Far Red staining. Spearman's correlation analysis examined relationships between viable SDF, total SDF, and standard semen parameters. Using the 25% total SDF cutoff, patients were grouped into high (≥25%, n=96) and low (