At last, the automated semen analysis is here!

In the investigation of infertile couples, semen analysis and cytology are always the first-line examinations. The manual technique remains the gold standard and most medical laboratories can carry out these examinations, even if prescribers prefer them to be carried out in a specialist andrology laboratory because of the significant variations between laboratories. Multicentric studies have shown that sperm concentration, one of the least subjective parameters analysed, has inter-laboratory coefficients of variation (CV) ranging from 21% to 80% (Brito et al., 2016). These variations – that are mainly due to differences between individual operators – have led us to move towards the automation of semen analysis. Although automation is very widely used in medical laboratories, little use has been made of it specifically in the field of spermiology. CASA devices (Computer Assisted Sperm Analysis) appeared on the market in 1985 with regular technical developments since then (review in Amann & Waberski, 2014) but their results are quite inconsistent and their software is often adapted in terms of morphology to a different classification system to that commonly used in France. The arrival on the market of more suitable devices, the establishment of ISO 15189 norm with its procession of quality controls and the need to ensure decreasing inter- and intra-laboratory variations have created an opening for these CASAs. In our laboratory we evaluated the Sperm Class Analyser (SCA, Microptic*, Spain) by comparing it to the standard manual technique. We also implemented a technical modification so that for the first time we can offer a morphological analysis according to the French classification, David as modified by Auger (Auger et al., 2016).

The SCA system consists of a microscope equipped with a digital camera, a motorized heating stage, and image analysis software (Microptic SL*) with an analytical filter that eliminates inconsistent analysis events (cell debris, isolated heads or flagellae).

The automated analysis of the sperm concentration, motility, vitality and morphology obtain very similar results when compared the manual method (for each parameter at least 30 sperms were evaluated). These comparisons were conducted on a large number of patient samples to cover all the normal and pathological conditions of each parameter, and also to take into account the great variability of the sperm samples for the same patient, which is a particular difficulty with this analyte. These 2 methods are therefore comparable (normal distribution of populations and comparison by calculating the regression line by the least squares method).

Moreover, for each of the parameters studied, the repeatability CVs decrease significantly with the automated analysis. For example, for normal sperm, with manual and automated analysis there are respectively CVs of 9.0% and 4.4% for sperm concentration, 7.3% and 2.4% for vitality and finally 11.4% and 4.1% for morphology.

The latest generation of CASAs with their fast and reliable analyses have become invaluable tools in the routine analysis of the key parameters of the spermogram. Technicians who are already qualified in manual spermiology rapidly learn to use the CASA. However, it is unlikely that this technology will entirely replace manual expertise, especially in the case of very low concentration values where the system comes up against its limits. The manual skills of spermiology technicians will therefore still be required by laboratories.

The use of the CASA system, even though its unit cost is still high, brings to the medical laboratory an improvement in the robustness of results for an analyte which already has very large normality ranges (WHO, 2010). It is also the first time that a CASA system can generate sperm morphology results according to the David classification as modified by Auger (Auger et al., 2016).However the SCA software is also able to analyze sperm morphology according the strict criteria of the WHO (2010)

More informations

• Amann RP & Waberserski D. (2014) Computer-assisted sperm analysis (CASA): capabilities and potential developments. Theriogenology 81, 5–17.
• Auger J, Jouannet P & Eustache F. Another look at human sperm morphology. (2016) Hum Reprod 31, 10–23.
• Brito LFC, Althouse GC, Aurich C, Chenoweth PJ, Eilts BE, Love CC, Luvoni GC, Mitchell JR, Peter AT, Pugh DG & Waberski D. (2016) Andrology laboratory review: evaluation of sperm concentration. Theriogenology 85, 1507-1527.
• World Health Organization. (2010) WHO laboratory manual for the examination and processing of human semen (5th edn), WHO Press, Geneva.