Technical Aspects and Clinical Limitations of Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

Abstract

Purpose Sperm DNA fragmentation (SDF) is a functional sperm abnormality that can impact reproductive potential, for which four assays have been described in the recently published sixth edition of the WHO laboratory manual for the examination and processing of human semen. The purpose of this study was to examine the global practices related to the use of SDF assays and investigate the barriers and limitations that clinicians face in incorporating these tests into their practice. Materials and Methods Clinicians managing male infertility were invited to complete an online survey on practices related to SDF diagnostic and treatment approaches. Their responses related to the technical aspects of SDF testing, current professional society guidelines, and the literature were used to generate expert recommendations via the Delphi method. Finally, challenges related to SDF that the clinicians encounter in their daily practice were captured. Results The survey was completed by 436 reproductive clinicians. Overall, terminal deoxynucleotidyl transferase deoxyuridine triphosphate Nick-End Labeling (TUNEL) is the most commonly used assay chosen by 28.6%, followed by the sperm chromatin structure assay (24.1%), and the sperm chromatin dispersion (19.1%). The choice of the assay was largely influenced by availability (70% of respondents). A threshold of 30% was the most selected cut-off value for elevated SDF by 33.7% of clinicians. Of respondents, 53.6% recommend SDF testing after 3 to 5 days of abstinence. Although 75.3% believe SDF testing can provide an explanation for many unknown causes of infertility, the main limiting factors selected by respondents are a lack of professional society guideline recommendations (62.7%) and an absence of globally accepted references for SDF interpretation (50.3%). Conclusions This study represents the largest global survey on the technical aspects of SDF testing as well as the barriers encountered by clinicians. Unified global recommendations regarding clinician implementation and standard laboratory interpretation of SDF testing are crucial.

Sperm DNA fragmentation in male infertility: From bench to bedside

“…Currently, four assays for measuring SDF levels are included in the WHO manual and can be used in clinical practice, based on availability, expertise, and resources [ 5 , 11 ]. These include the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay, the sperm chromatin structure assay (SCSA), the sperm chromatin dispersion (SCD) assay, and the Comet assay.…”

“…Table 1 summarizes the techniques, advantages, and disadvantages of these four assays. Since prolonged ejaculatory abstinence may result in elevated SDF levels [ 17 ], SDF testing is recommended with less than 5 days of abstinence duration [ 11 ]. Regarding interpretation of SDF results, the consensus is that each testing laboratory establishes and reports its own reference values [ 11 ].…”

“…Since prolonged ejaculatory abstinence may result in elevated SDF levels [ 17 ], SDF testing is recommended with less than 5 days of abstinence duration [ 11 ]. Regarding interpretation of SDF results, the consensus is that each testing laboratory establishes and reports its own reference values [ 11 ]. This recommendation acknowledges a major limitation in SDF testing, where no standardized cut-off exists.…”

Gaussian clustering and quantification of the sperm chromatin dispersion test using convolutional neural networks

“…Though with relatively acceptable individual test agreement, 25 the current SCD test has long been criticized for high inter-observer variability. 24,26 According to WHO's recommendation, laboratory technicians evaluate the ratio of the halo size and the transverse diameter of the sperm head by the eye under a light microscope. The sperm DNA is considered fragmented if the ratio is less than 1/3.…”