The Sperm DNA Fragmentation Test or SCSA Test is an advanced male infertility test evaluating the DNA integrity of the sperm. SCSA stands for Sperm Chromatin Structure Analysis. Other names describing the same test are the sperm DNA fragmentation test and sperm chromatin fragmentation test.
Infertility, IVF failures, and miscarriages can be caused by sperm DNA fragmentation (SDF), which is the abnormal genetic material within sperm.
As a result of the Sperm DNA Fragmentation test, valuable information can be gained about the genetic quality of the sperm. This allows for an accurate assessment of male infertility and subsequent treatment planning.
Generally, if the DNA fragmentation is less than 15%, the sperm is considered excellent. If the DFI (dna fragmentation index) is between 15% to 25%, then the sperm is of good quality.
Recently, there has been increased emphasis on evaluating sperm quality. Unfortunately, a sperm or semen test by itself is of limited value. Sperm counts, for example, fluctuate significantly from day to day in most men.
When you think about it, sperm are nothing more than transport vehicles to get DNA from the male into the female egg. Since sperm are very small, a large amount of DNA must be "crammed" into a tiny container. The DNA is wound, twisted on itself, and wrapped around blocks of protein.
The combination of DNA and protein blocks is chromatin. Part of the function of the protein blocks is to protect the sperm DNA from damage during its long journey from where it is produced (in the testicles) to where it hopefully arrives (the egg). However, it seems that some DNA will remain susceptible to damage and that DNA can become fragmented.
When is DNA fragmentation test recommended?
- Infertility that cannot be explained
- Development of embryos is poor
- Failures of intracytoplasmic sperm injections (ICSI) and in vitro fertilization
- Having a miscarriage
- Advanced age of the male patient
- Poor semen quality
- Being exposed to harmful chemicals
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How is Sperm DNA Fragmentation Test performed?
Several tests have been developed to assess the percentage of spermatozoa with significant DNA fragmentation. One of them is called the TUNNEL assay. Another is called the COMET assay. However, the test that has received the most attention recently is called the SCSA or sperm chromatin structure analysis.
During the SCSA test, spermatozoa are treated with a chemical to allow entry of a special dye into the sperm cell. The dye sneaks its way into crevices in the DNA molecule. In theory, sperm with fragmented DNA takes up more of the dye.
Then, using the flow cytometry procedure, the sperm that took up lots of dye (the sperm with fragmented DNA) can be differentiated from the sperm that took up only a little dye (sperm with normal DNA). Finally, using a computer program, each sperm cell can be graphed out, and the lab can determine the percentage of sperm with fragmented DNA.
Significance of the SCSA test
Some early clinical data involving SCSA suggested that men with more than 30% of their DNA with fragmentation had very low pregnancy rates (1% or less) even with aggressive techniques such as in vitro fertilization - IVF. However, this is not entirely true.
The best conclusions we can make today about an abnormal SCSA test are:
- All men, whether fertile or infertile, have some sperm with fragmented DNA.
- Men with a normal semen analysis can have an abnormal SCSA.
- An SCSA test result is very consistent over time. The SCSA is more consistent than semen analysis. However, some things can cause an abnormal test, such as a high fever or certain medications. Certain steps in preparing to do the test can affect the results of the SCSA.
- The best evidence to date suggests that men with an abnormally high percentage of sperm with DNA fragmentation have a pregnancy rate similar to men with a normal percentage of sperm DNA fragmentation when using techniques such as IVF with ICSI.
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Can sperm fragmentation be reduced?
Yes, it is possible if you:
- quit smoking and drinking
- repair your varicocele (if there is one)
- reduce exposure to heat (avoid tight underwear, very hot baths, don't work with your laptop on your lap for long hours)
- exercise and lose weight
- eat healthy
- use vitamin C, E, zinc, selenium and coenzyme Q-10, although more research and scientific proof are needed