Sperm DNA Fragmentation Testing
Author : Doctor Ahmed Abd El-Aziz
• Updated at: Jun 09, 2024 •
Sperm DNA fragmentation is a term used for abnormal genetic material in the sperm cell. The genetic material that during fertilization is passed on to a next generation is carried in the DNA of a sperm cell. Sometimes this DNA can be damaged due to various reasons, leading to infertility, miscarriage, and abnormal sperm function. Healthy spermatozoa (sperm cells) and oocytes (eggs) are necessary for developing a healthy embryo! Genetic material damage can occur in the male spermatozoa and the female oocytes. Sperm DNA fragmentation testing is a test that can provide answers to failed IVF/ICSI trials and recurrent abortion.
Sperm DNA fragmentation
Each spermcell and egg contain 23 chromosomes after fertilization the embryo cell has 46 chromosomes, a set of 23 from each parent.
Chromosomes consist of a long DNA molecule that contain part of the genetic material which makes every living organism unique. In the case of sperm cells deletion or damage(depending on the amount of it) in this molecule can lead to defragmentation of DNA in sperm
Broken or damaged DNA is common in the human body, but cells are programmed to auto-repair and correct the damage. If the sperm cell is still immature and went through some kind of DNA separation or breakage, it can auto-repair according to the genetic code, but if the sperm is already mature this can be hard for the sperm cell to accomplish.
Studies show that men with high sperm DNA fragmentation percentages can conceive but there is a higher miscarriage rate or failure for embryos to develop correctly.
Sperm DNA fragmentation testing
Sperm DNA fragmentation should be considered if there were several trials of failed IVF/ICSI, Recurrent abortion or unexplained fertility.
Sperm DNA defragmentation does not show in a normal semen analysis, the testing of sperm DNA fragmentation is done in special laboratories that have the right staff and equipment.The testing of sperm DNA fragmentation is en extra measure to ensure the sperm quality in patients with recurrent IVF/ICSI failure or abortion.
There are several methods to conduct the test, but the one most widely used is the Tunnel method, which we use in Bedaya Hospital. In this method every cell in the head of the sperm is analyzed to detect any defect in the genetic material.
Sperm DNA fragmentation test normal range
One of our andrologists performs a DNA fragmentation test in the lab after semen is evaluated and treated with an acid soluion that allows the release of genetic material. A portion of the treated sperm is mixed with a drop of a special solution and put on a glass slide to be viewed under a special type of microscope. After a short period of time the sperms spread within the solution, if the sperms are healthy - it produces a distinctive halo around the sperms so they can be seen under a microscope. If there is damage to the sperm's DNA, the areola is very small or not visible at all. The DNA Fragmentation Index (DFI) is calculated by evaluating the number of gamaged sperm represented in the semen sample taken.
15% or less fragmentation – excellent sperm DNA integrity
15-to 25% DFI – good to fair
25 – 50% DFI – fair to poor
50% or greater DFI – extremely poor sperm DNA integrity
Sperm DNA fragmentation testing is very useful for all those with failure of fertilization after IVF/ICSI, recurrent abortion and unexplained infertility, it gives the doctor and couple information about a possible treatable cause for infertility.
