Evaluation of subgroups of the human sperm hypoosmotic swelling test in normozoospermic male cases with recurrent fertilization failure: a prospective case-controlled study.
To compare subgroups of the human sperm hypoosmotic swelling test subgroups in both recurrent fertilization negative infertile cases with normal semen analysis and fertilization positive controls. This was a prospective case-controlled study performed with normospermic 33 previously fertile male (secondary infertility) and 41 infertile men who had undergone two or three unsuccessful in vitro fertilization attempts. HOS test was investigated in 4 subgroups including HOS 1, HOS 2, HOS 3, and HOS 4 according to the degree of sperm tail swelling and compared between the two groups. Four subgroups were compared and statistical significance was demonstrated in HOS 1, HOS 3 and HOS 4 tests (p < 0.001) in fertile and infertile men. Highest HOS 1 and lowest HOS 4 grades were determined in Group A. However, no statistical significance was determined between two groups in HOS 2 test which was minimal swelling in sperm tails. HOS 1, HOS 3 and HOS 4 subgroups of HOS test are reliable and useful methods providing important information regarding the sperm function. A high HOS test 1 grade plus a low HOS test 4 grade should suggest a fertility problem, despite a normal semen analysis. HOS test subgroups provide additional information in normospermic cases with unexplained infertility.