Letters to the editor |
Reply: Development of a novel home sperm test - temperature range
To whom correspondence should be addressed at: Division of Reproductive and Child Health, The Medical School, University of Birmingham, Birmingham, B15 2TT, UK. E-mail: c.barratt{at}bham.ac.uk
Sir,
We are very grateful for the comments from Dr Marik regarding our publication on the home sperm test (see Björndahl et al., 2006
). We are pleased to see the considerable interest generated by our experiments.
First, we agree that the test offers the man an opportunity to assess his potential fertility in the comfort of his own home. Second, the device is very simple to use. As a separate evaluation to the one we have reported, the ease of use of the device was assessed on 433 subjects across three study sites (two in the US, the other in the UK). Feedback from the users demonstrated that the device is easy to use. The device has been cleared for OTC home use by the FDA. We cannot comment on the market sales.
With regard to the main point—temperature control. Sperm motility is dependent on temperature (see Ford et al., 1992). As the device detects the presence of motile sperm that have penetrated hyaluronate, it is very important to regulate temperature. In a series of preliminary experiments, we noted a marked variation in the penetration into an artificial cervical mucus substitute (methylcellulose; see Ivic et al., 2002), especially over the temperature ranges 17–30°C. However, we did not detect significant differences in the numbers of spermatozoa penetrating methylcellulose when incubated at 30 or 37°C.
We clearly state in our publication that the temperature of the semen sample does not rise above 32°C. To date, our clinical trials have used a number of different batches of devices to verify batch to batch consistency and have shown a high degree of accuracy (>95% when compared with the Hamilton Thorn and modified Kremer testing). Thus, we believe that the temperature-control mechanism employed in the device is a robust, reproducible and reliable method of addressing the variation in ambient temperature in the home test environment.
References
Björndahl L, Rattle S, Hart G, Kirkman-Brown JC, Barratt CLR. (2006) Development of a home sperm test. Hum Reprod 21:145–149.
Ford WC, Ponting FA, McLaughlin EA, Rees JM, Hull MG. (1992) Controlling the swimming speed of human sperm by varying the incubation temperature and its effect on cervical mucus penetration. Int J Androl 15:127–134.[Web of Science][Medline]
Ivic A, Onyeaka H, Girling A, Brewis IA, Ola B, Hammadieh N, Papaioannou S, Barratt CLR. (2002) Critical evaluation of methylcellulose as an alternative medium in sperm migration tests. Hum Reprod 17:143–149.
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