Sperm DNA fragmentation

High sperm DNA fragmentation (SDF) is associated with reduced natural pregnancy rates and assisted conception pregnancy rates as well as live birth rates. Sperm DNA fragmentation also leads to higher miscarriage rates, as published in the ESHRE Recurrent Pregnancy Loss 2017 Guideline. High levels of DNA fragmentation may be reduced by considering varicocele repair, treatment of underlying infections or inflammation, changes in lifestyle, or with antioxidant supplements.

Sperm DNA can be damaged when sperm are being made in the testes or as they mature before ejaculation. This damage breaks the DNA into fragments, so sperm DNA tests are also known as sperm DNA fragmentation tests. Men with high levels of sperm DNA damage are less likely to get their partner pregnant and have increased risk of miscarriage. Even if semen analysis results are ‘normal’, the sperm DNA could be damaged and therefore poor quality. 

When requesting Sperm DNA Fragmentation there are two options. Please specify whether the request is for sperm DNA fragmentation by SCSA or COMET.

Sperm Chromatin Structure Assay (SCSA type test) [SEXT] 

This test has the ability to measure large numbers of cells (between 5,000 and 15,000 sperm), rapidly in an ejaculate. The SCSA test monitors the changes in fluorescence of a probe using Acridine Orange Flowcytometry test, to detect both single and double DNA strand breaks. It has been developed using human and animal models over the last 35 years and is one of the most statistically robust tests available for sperm DNA fragmentation. It is a standardised, validated CLIA approved test with high reproducibility and low variability. The test requires a minimum sperm count of approximately 100,000/ml.

Sperm COMET® Assay [CMET / CMET2 / CMET3 / CMET4] 

Exact® tests, powered by SpermComet technology measure sperm DNA damage. 

The COMET® assay sperm DNA fragmentation (SDF) tests from Examen® provide one of the highest performance levels among commercially available SDF tests. The COMET® tests directly measure total single- and double-strand DNA breaks (CMET / CMT2), and double-strand breaks only (CMT3 / CMT4). Use Examen’s COMET® tests for

• couples struggling to achieve pregnancy (idiopathic infertility), especially where a semen analysis was ‘normal’, or where there have been repeated failed IVF cycles (CMET / CMT2)
• couples struggling to keep the pregnancy / suffering multiple recurrent pregnancy loss, especially if multiple early losses <14 weeks, and female aged mid-thirties and above (CMT3 / CMT4)

It has the advantage of requiring only 5000 sperm so it can be used for men with low sperm counts and for surgically retrieved sperm samples. There are 4 types of COMET tests available at different costs. The clinician must select the desired type prior to sending the patient as well as ensuring completion of the Examen request form. 

Download Examen Request Form

Instructions for collection of Sperm DNA fragmentation and Aneuploidy specimens 

Sperm DNA Fragmentation or Sperm Aneuploidy testing are not part of the Comprehensive Semen Analysis and need to be requested as a separate test, test code SEXT, CMET1-CMET4 and SPPL, respectively. 

Semen samples ideally need to be frozen as soon as possible after liquefaction, but not longer than 60 minutes post ejaculation. Samples must be snap-frozen for Sperm DNA Fragmentation and cryopreserved in TYB for Sperm Aneuploidy. If samples are prepared by another laboratory. Two cryovials containing not less than 0.25 mls of semen is required. Frozen samples can be sent to, or collected by TDL, by arrangement, and must be accompanied with relevant patient details andthe sperm count. For CMET test please ensure a completed Examen request form accompanies the TDL request form.

A count of a minimum 0.1 million/ml is required for accurate DNA fragmentation and aneuploidy reporting.