I What else can sperm tests check for pregnancy?
Sperm tests have become increasingly sophisticated and can now be used to test for a whole range of factors that can potentially affect fertility. These tests would not necessarily be part of a standard NHS test and need to be paid for, but they can reveal invaluable information. This might include:
Acidity of semen (sperm is usually alkaline with a pH between 7.2 and 8).
Agglutination: this means that motile sperm stick to one another and usually indicates the presence of antisperm antibodies (proteins that coat sperm and bind to cervical mucus, preventing sperm from moving towards an egg or fertilizing it). If sperm are sticking to each other, a MAR (mixed agglutination reaction) test will be needed. In healthy sperm this should show less than 50 per cent binding and should not affect fertility.
K Presence of antibodies: these are not usually present in semen, however they may be caused by injury or surgery such as vasectomy reversal or hernia repair, where a breakdown in the blood-testis barrier allows blood and testicular tissue to mix. When antibodies are present at relatively high levels, fertility may be affected. As well as preventing sperm from moving, they may coat the sperm heads, making it difficult for them to recognize an egg and fertilize it.
K Concentration of round cells (these are either immature sperm cells or white blood cells). A raised concentration of these may indicate an infection, which if serious can result in permanent damage.