The Sperm DNA Integrity assay (SDIA) like the Sperm Chromatin Structure Assay
(SCSA) is a tool for measuring clinically important properties of sperm nuclear chromatin integrity. Chromatin is that portion of the cell nucleus which contains the entire DNA of the nucleus in animal or plant cells.
The results correlate well with the potential of sperm from a given male to produce embryos that would be sufficiently “competent to produce a live birth. The SDIA utilizes the metachromatic features of acridine orange (AO), a DNA probe, and the principles of flow cytometry (FCM).
SDIA data are not well correlated with classical sperm quality parameters and have been solidly shown to predict sub/infertility and poor reproductive performance. The SDIA measures DNA damage. The degree of abnormalities in the genetic material of the sperm is expressed numerically as the DNA Fragmentation Index (DFI). DNA damage may be present in sperm from both fertile and infertile men. Therefore, this sperm DNA damage analysis may reveal a hidden abnormality of sperm DNA in infertile men classified as unexplained based on apparently normal standard sperm parameters.
Infertile men with abnormal sperm characteristics exhibit increased levels of DNA damage in their sperm. Sperm from infertile men with normal-appearing sperm may have DNA damage to a degree comparable to that of infertile men with abnormal-appearing sperm. The data suggests that an abnormal SDI assay is more likely to occur in cases of abnormal semen parameters.
Cancer treatments are well known to adversely affect male fertility. Reduction of sperm output arises from the cytotoxic effects of chemo-or radiotherapy upon the spermatogenic epithelium.
Optimal sperm chromatin packaging seems necessary for full expression of the male fertility potential. SDI assays emerge as predictors of the probability to conceive and carry the pregnancy to viability.
The improvement seen in sperm motility after treatment is not associated with a similar improvement in sperm DNA integrity (SDIA assay results). These data suggest that sperm processing techniques will not minimize sperm DNA damage and the potential transmission of genetic mutations in assisted reproductive cycles.
It is important to add that most current data available on the significance of abnormal SDIA results in infertile couples seeking treatment has emanated from non-IVF pregnancies.
Preliminary data suggests the following:
The viable (>12 weeks) IVF pregnancy rate (and thus presumably also the birth rate) could be as much as 2 times lower in women under 33yrs of age, whose husbands have abnormal SDI assays ( with a DFI of