[Diagnostic value of sperm DNA fragmentation for male infertility].

OBJECTIVE: To assess the diagnostic value of sperm DNA fragmentation (SDF) for male infertility. METHODS: Two hundred and ninety-nine males attending infertility clinic were classified into 157 primary infertile cases and 142 fertile controls. Semen analysis was performed as recommended by the World Health Organization (WHO). SDF was assessed by sperm chromatin dispersion (SCD) assay, and the results were expressed as DNA fragmentation index (DFI). RESULTS: The DFI was significantly higher in infertile males than that in fertile controls [(17.1± 9.3)% vs. (14.2± 9.0)%](P< 0.01). No significant difference was detected in the age of male and female partners, seminal volume, sperm count, motility and morphology between infertile males and fertile controls (P> 0.05). The area under the receiver operating characteristic curve (AUC) was 0.861 [95% confidence interval (CI)= 0.814-0.907] for 15.1% of SDF. The threshold level of 15.1% was derived as cut-off value to discriminate infertile men from fertile controls. By this threshold, specificity was 88.2% and sensitivity was 81.8%. The 299 men were divided into group A (n= 120) with DFI≥ 15.1% and group B (n= 179) with DFI< 15.1% based on the cut-off value. The percentage of infertile men in group A was significantly higher than that in group B (79.2% vs. 34.6%) (P< 0.01). The odds ratio (OR) for infertility in the two groups was 7.2 (95%CI= 4.2-12.3). CONCLUSION: Sperms with high-level of DNA fragmentation can impair male fertility. DFI can be used as a good diagnostic marker for male infertility.