DNA fragmentation index (DNAFI) testing measures the quality of the DNA contained within sperm. It is reported as a percentage of sperm DNA that has "breaks" in the DNA strands.
Sperm DNA fragmentation is associated with infections, cigarette smoking, drug use, exposure to environmental and occupational pollutants, aging, varicocele (enlarged veins inside the scrotum), illnesses with high fevers, elevated testicular temperature (laptop computers, hot tubs), chronic diseases such as diabetes, cancer and cancer treatment, poor diet, and obesity. DNA fragmentation occurs when the body is unable to repair breaks that occur in DNA.
Increased DNA fragmentation rates may make it more difficult to achieve a successful pregnancy both naturally, and using artificial reproductive technology such as intrauterine insemination or in-vitro fertilization.
Why it's done
There are a few specific situations where a DNAFI test may be valuable, including:
- Varicocele. Men who have a varicocele (enlargement of the veins of the testicle), but normal sperm counts may benefit from a DNAFI test to see if their sperm DNA fragmentation rates are high. If their DNA fragmentation rates are high, they want to consider undergoing surgery to repair the varicocele, which may improve their fertility.
- Unexplained infertility or recurrent miscarriage. DNAFI testing is also indicated for couples where both partners have had a negative workup and there is not explanation for why they are having trouble getting pregnant, or for couples who have had a recurrent miscarriage. If DNA fragmentation rates are high, they want to consider proceeding directly to in-vitro fertilization.
- Intrauterine insemination failure. Couples who were not able to get pregnant using intrauterine insemination may consider DNAFI testing to see if in-vitro fertilization would be a better option.
- In-vitro fertilization and/or intracytoplasmic sperm injection failure. Couples who have failed multiple in-vitro fertilization cycles may want to consider DNAFI testing to see whether it would be beneficial to undergo a procedure called a testicular sperm extraction (TESE) to get sperm directly from the testicle. In men with high DNA fragmentation rates, sperm obtained directly from the testicle has been shown to have lower DNA fragmentation rates.
- Men with a borderline abnormal (or normal) semen analysis who have a risk factor. Men with borderline or even a normal semen analysis who have a lifestyle factor that they could change to improve their sperm counts (and potentially DNA fragmentation rates) may benefit from knowing their DNA fragmentation rate. Examples of lifestyle factors that contribute to DNA fragmentation include obesity, smoking, and exposure to environmental pollutants.
How to prepare
A DNAFI test is a semen test that can be collected in the lab or at home. You should ejaculate approximately 2 days before giving a sample so that the sample provided is a fresh sample. Abstain for 2 days prior to collecting a specimen, and avoid using any lubricants. If you must use a lubricant, PRE-SEED is the least likely to cause sperm DNA damage.
DNAFI testing is reported as a percentage of abnormal sperm DNA. The report you will receive typically lists three categories of fertility potential as follows:
- Excellent to Good fertility potential: <15% DNAFI
- Good to Fair fertility potential: 15-25.0% DNAFI
- Fair to Poor fertility potential: 25-50.0% DNAFI
- Very Poor Sperm DNA integrity: >50% DNAFI
Research shows that the probability of a successful pregnancy is significantly reduced when the DNAFI is greater than 25%.