DNA Fragmentation Index (DFI)

What is DNA Fragmentation Index (DFI) Test?

DFI test full form translates to the DNA Fragmentation Index test, a test that measures the integrity of DNA present in the sperm’s head. DNA fragmentation is expressed in terms of the DNA fragmentation index (DFI). Research studies highlight that the rates of conception are statistically lower among couples with an elevated semen DFI.

Sperm DNA fragmentation shall be described as a change or deletion in bases or the breakage or separation in one or both strands of the DNA contained within the sperm. DNA fragmentation includes both single and double DNA strand breaks.

Advantages and utility of taking the DFI test?

• The test shall help to identify men with the risk of subfertility.
• DFI results provide valuable information which can help in the diagnosis, management, and treatment of male infertility

Semen analysis and DFI sperm test:

Semen analysis is the most common way of measuring the features like size, shape, concentration, and motility of the sperm. It has been prevalent for a long time and is often called a golden standard test for determining a man’s fertility. But it leaves behind the genetic makeup of the sperm.

If we consider the normal process of reproduction, it is the sperm that fertilizes the egg and leads to zygote formation. But the role of sperm isn’t confined to fertilizing an egg. Instead, the genetic constitution of sperm is designed to serve the needs of embryo development. Thus, sperm DNA is a significant part of embryo development.

DFI test results: What is a DFI test normal range?

The results of the DFI sperm test are solely dependent on two factors –

• DNA Fragmentation Index (DFI) – Less than 15% is DFI is the excellent quality of DNA integrity, on the other hand, more than 50% of DFI indicates a poor DNA integrity
• High DNA sustainability (HDS) – More than 25% of sperms with immature chromatin shall be taken as unsuitable for pregnancy.

Relation between sperm cells and genetic integrity?

Sperm cells serve the purpose of transporting DNA to the female gamete. They are designed in such a manner that the precious chromosomes are carried effectively to the eggs. DNA present in the head holds all the instructions necessary for the development of an embryo and thus the genetic integrity of sperm is a significant part of fertility. A damaged DNA within a sperm could interfere with the sperm’s ability to fertilize an egg. Not just fertilization, the complications extend further to the development of an embryo. This is how sperm DNA fragmentation affects fertility. DFI fertility test is a diagnostic tool that evaluates the degree of fragmentation of sperm thus reflecting upon the extent of damage.

DFI test procedure:

The DFI test procedure is somewhat similar to that of a regular semen analysis method. Semen samples are taken and tested at the center. The technique used in the test is called Sperm Chromatin decondensation which is based on the differentiation between sperms based on the expanded nuclei. The technique makes use of a Halosperm kit. The process has been developed with a comet test, tunnel test, and light microscope-based SCD tests. The test can be easily conducted along with semen analysis.

Effects & Benefits of DNA Fragmentation Index Test

DNA problems in embryo shall be highlighted as:

• Cellular degeneration
• Gene mutations
• Arrested embryo growth
• Miscarriage
• Irregularities in children
• Higher susceptibility to childhood cancer problems and more.

Reasons behind sperm DNA fragmentation?

Extrinsic factors that cause sperm DNA fragmentation include:

• Lifestyle (obesity, alcohol, and smoking)
• Radiations
• Varicocele
• Chemical toxins
• Ageing (advance age)
• Genital Tract Infections.

Intrinsic factors that cause sperm DNA fragmentation include:

• Oxidative stress
•  A structural defect in DNA
• Apoptosis before maturation of sperm
• Genetic mutation.

Need for a DFI test:

The index reflects the percentage of sperm in a particular semen sample with fragmented DNA. This test is a useful add-on to the routine semen analysis. It helps in diagnosing infertility problems right at the genetic level and is therefore significant.

High DFI

A DFI test report that shows sperm with 30% or more DFI indicates that more than 30% of sperm have fragmented DNA. This rate is found to impact the fertility potential of the sperm and usually, such samples are more prominent in men with infertility. Anything more than 30% demands ICSI and special days of selecting sperms as a fertilisation method. This is termed high DFI.

Potential risks of high DFI?

Women with partners who have high DFI are found to be at risk of forming poor-quality embryos. Patients undergoing high DFI treatment often have questions regarding high DNA fragmentation and icsi success and sperm DNA fragmentation test cost. Research finds that the fertilisation rates in the IVF and ICSI cycles in the high-DFI group were significantly higher than the rate in the IVF cycles and were similar to the rate of ICSI cycles in the low-DFI group.

DFI in IVF: Can DNA fragmentation cause miscarriage in IVF patients?

Research highlights that sperm DNA damage is associated with pregnancy loss. It is more recognized in the early stages and may be implicated in recurrent miscarriages as well.

A study of IVF patients highlights that the couples in which the male partner had high levels of sperm DNA fragmentation are significantly more likely to experience miscarriage as compared to the couples in which the male partners have a low sperm DNA fragmentation rate.Experts believe that high sperm DNA fragmentation compromises embryo viability which results in pregnancy loss.

DFI in IVF: what are the recent trends of IVF and DFI?

Both IVF and sperm DNA fragmentation hold the same trend – a higher rate correlating with lower live birth rates. It has been found that in many cases DNA fragmentation can predict the outcome of ART ( assisted reproductive technology).

Thus, it can be concluded that sperm DNA fragmentation impacts fertility independently of other semen parameters.  In a research study of IUI (intrauterine insemination), IVF, and ICSI (intracytoplasmic sperm injection) , it was found that a high DNA fragmentation index had the power to predict whether or not a couple would achieve pregnancy. In this study, pregnancy rates for couples with high DNA fragmentation index were less than half that of low-DFI couples thus making it clear that DFI sperm analysis could provide insights into infertility and its desired treatment.