Sperm DNA Fragmentation test/Sperm Chromatin structure assay
What is the SCSA® test?
The SCSA, or Sperm Chromatin Structure Assay, test quickly and accurately identifies men who are less likely to achieve a term pregnancy naturally or with IVF. It does this by determining the percentage of sperm with high levels of DNA fragmentation, i.e. the DNA Fragmentation Index (% DFI).
The test is based on well-established research and methods. Developed over the course of more than 20 years, the SCSA has been the subject of more than 125 articles published in peer-reviewed journals and periodicals.
What is sperm chromatin?
The 23 chromosomes in the sperm head are made up of chromatin, which consists of DNA and proteins.
What unique information does the SCSA provide about male infertility?
SCSA data suggest a clinically relevant threshold for evaluation of male infertility. Clinical studies show that if >30% of the sperm in a semen sample have DNA fragmentation (>30% DFI), the probability for a successful pregnancy is significantly reduced.
Can sperm with normal shape and motility have high levels of DNA fragmentation as assessed by the SCSA?
Although less likely, sperm with normal shape and motility may have high levels of DNA fragmentation. Therefore, the SCSA identifies male infertility that may not be identified by any conventional semen analysis.
If a semen sample has a high percentage of sperm with fragmented DNA, is this condition permanent, or might it improve over time?
SCSA results are significantly more stable than results obtained by conventional semen analysis. However, a small percentage of men bordering on infertility may have relatively unstable DNA quality as assessed by the SCSA. These men may have poor fertility potential (>30% DFI) for a few months and then dramatically improve with pregnancy occurring during the month when SCSA data shows low levels of DNA fragmentation. Therefore, a second test is recommended in two to three months following poor SCSA results.
What causes elevated levels of DNA fragmentation?
DNA fragmentation in sperm may be the result of many factors including, but not limited to oxidative stress, disease, diet, drug use, high fever, elevated testicular temperature, air pollution, cigarette smoking and age (upper 40's and beyond).
Where are the Department of Health and Human Services certified laboratories (CLIA) for the SCSA?
At this time, SCSA Diagnostics in South Dakota is the only laboratory approved by CLIA for the SCSA. CLIA certification provides assurance that the assay will be conducted to the highest standards and that patient data will be handled and archived in an appropriate manner.
How are semen samples sent to SCSA Diagnostics?
A small portion of raw, liquefied semen is pipetted into a tube and placed in a liquid nitrogen (LN2) tank where the sample immediately freezes. The LN2 tank, including the frozen sample, is shipped overnight from the patient's clinic or home to SCSA Diagnostics by Federal Express.
What does the SCSA Clinical Report show?
Our SCSA clinical report lists three statistical categories of fertility potential. These were derived from a comprehensive study of male fertility potential without medical interventions:
Excellent fertility potential ~ <15% DFI
Good fertility potential ~ 15-29.9% DFI
Poor fertility potential ~ >30% DFI
Current data show the probability of a successful pregnancy is significantly reduced when the percentage of sperm with fragmented DNA is >30%.
Can the SCSA test measure the sperm DNA fragmentation levels of all men?
No. SCSA test results may be inconclusive for men with an extremely low sperm count (<500,000/ml to 750,000/ml) and/or a high level of seminal debris. It is important that patients consult with their physician to consider these factors before ordering the SCSA test.
Does the SCSA test measure sperm chromatin abnormalities other than DNA fragmentation?
In addition to DFI, the SCSA test identifies a fraction of sperm with High DNA Stainability (HDS). HDS sperm are considered to be immature with unprocessed nuclear proteins and/or poorly condensed chromatin. Preliminary data indicate that semen samples with a high percentage of HDS sperm (>15%) may have lower fertilization rates with conventional IVF (but not with ICSI).