Increased sperm nuclear DNA damage in normozoospermic infertile men: a prospective study
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Updated: Sep 30, 2026

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects
Published on: April 21, 2022
Ramadan A Saleh1, Ashok Agarwal, David R Nelson
1Center for Advanced Research in Human Reproduction, Infertility, and Sexual Function, Urological Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Objective:
To evaluate levels of sperm nuclear DNA damage in infertile men with normal and abnormal standard semen parameters.
Design:
Prospective study.
Setting:
Male infertility clinic.
Patient(S):
Ninety-two men seeking infertility treatment and 16 fertile volunteers.
Intervention(S):
Standard semen analysis was performed according to the World Health Organization guidelines.
Main Outcome Measure(S):
Sperm DNA damage was assessed by sperm chromatin structure assay and the results expressed as %DFI.
Result(S):
Of the 92 patients, 21 (23%) had normal standard sperm parameters (concentration, motility, and normal sperm forms), while 71 (77%) had an abnormality in one or more of these parameters. The %DFI [median (25th and 75th percentiles)] in infertile men with normal sperm parameters [23 (15, 32)] was significantly higher than fertile donors [15 (11, 20)] (P=.02), but not significantly different from infertile men with abnormal sperm parameters [28 (18, 41)] (P=.27).
Conclusion(S):
The results of this study indicate that a significant increase in SCSA-defined DNA damage can be found in sperm from infertile men with normal standard sperm parameters. Therefore, sperm DNA damage analysis may reveal a hidden abnormality of sperm DNA in infertile men classified as idiopathic based on apparently normal standard sperm parameters.
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