SpermComet® is our proprietary technology powering the Exact range of sperm DNA tests. Independent research has shown that SpermComet® is the best performing DNA fragmentation assay in terms of sensitivity, specificity and predictive power. SpermComet® is the only DNA fragmentation assay guaranteed for testicular samples.
Exact tests, powered by SpermComet® technology, are the tests of choice amongst consultants in 80% of the UK’s leading fertility clinics.
All sperm DNA tests are not the same. Available tests measure different aspects of sperm chromatin damage and as a result have variable levels of diagnostic and prognostic strength (Table 1). SpermComet® is based on a technique known as single cell gel electrophoresis (SCGE). This technique is used extensively in drug toxicity research. Independent research has shown that the SpermComet® is the most sensitive assay for detecting DNA fragmentation (Figure 1 and 2). This is due to several unique features of the assay:
Detects actual DNA fragments: SpermComet® detects single- and double-strand DNA fragments present in individual sperm, making it a direct assay of damaged DNA. In contrast, both the Sperm Chromatin Structure Assay (SCSA) and Halo assays detect faults in the nuclear proteins protecting the DNA. Nuclear protein damage could make the DNA more vulnerable to damage, but it is not a measure of the actual damage to the DNA molecule itself.
Detects total DNA damage: Sperm DNA is up to 6 times more tightly packed than somatic cell DNA. The SpermComet® assay includes a decondensation step which relaxes the DNA exposing DNA strand breaks in the nuclear core. This step is necessary to detect total and not just peripheral DNA damage.
Quantifies amount of DNA fragmentation: Separation of the DNA fragments contained in individual sperm nuclei during electrophoresis allows the amount of DNA fragments to be quantified. In contrast, the other assays only measure either the presence or absence of chromatin or DNA damage.
Comparative analysis of three sperm DNA damage assays and sperm nuclear protein content in couples undergoing assisted reproduction treatment
Independent research has shown that the SpermComet® is the best assay for differentiating between fertile and infertile men (Table 2). It has a very high sensitivity and specificity in predicting male infertility. The high sensitivity of the SpermComet® means that it detects a high proportion of true positives i.e. samples likely to achieve a spontaneous pregnancy. The high specificity of the SpermComet® means that it also detects a high proportion of true negatives i.e. samples unlikely to achieve a spontaneous pregnancy.
The impact of sperm DNA damage in assisted conception and beyond: recent advances in diagnosis and treatment
Comprehensive analysis of sperm DNA fragmentation by five different assays: TUNEL assay, SCSA, SCD test and alkaline and neutral Comet assay
Conflicting research results have led to confusion about the relationship between sperm chromatin damage and ART outcomes. Much of this confusion can be explained by the fact that the type of assay used to measure sperm chromatin damage influences the detection of associations with ART outcomes. Recent independent research has shown that the SpermComet® is the only assay that is predictive of every early ART checkpoint including:
In the same research, the TUNEL assay showed no significant correlation with embryo or blastocyst quality and the SCSA assay was not predictive of any ART outcome (Figures 3-5). SpermComet® has been shown to have high sensitivity and moderate specificity in predicting pregnancy following ART (Table 3). The high sensitivity of the SpermComet® means that it detects a high proportion of true positives i.e. samples likely to achieve an ART pregnancy. The moderate specificity of the SpermComet® means that it also detects a good proportion of true negatives i.e. samples unlikely to achieve an ART pregnancy.
Measuring Sperm DNA Fragmentation and Clinical Outcomes of Medically Assisted Reproduction: A Systematic Review and Meta- Analysis
The effect of sperm DNA fragmentation on live birth rate after IVF or ICSI: a systematic review and meta-analysis