Sperm Membrane

Sperm Membrane Analysis (HOS test)

To confirm Sperm Fertilizing Potential

If routine semen analysis results repeatedly are within normal limits and when the couple are experiencing unexplained infertility or the partner is found to be “reproductively normal”, the fertilizing potential of the sperm should be checked by assessing the membrane integrity. To confirm, the ability of sperm to respond to hypo-osmotic stress; “Hypo-Osmotic Swelling” (HOS) test which determines the functional competence of the sperm membrane integrity should be checked. 

The concept of the HOS test is based on the ability of a living sperm to actively withstand the osmotic stress when exposed to hypo-osmotic conditions. The HOS test results are significantly associated with the outcome of zona-free hamster egg penetration and in-vitro fertilization. The HOS test results may predict in-vivo and in-vitro pregnancies, and recurrent pregnancy loss. It has been used to determine the effects of the therapeutic drugs on the functional integrity of the sperm membrane. 

Recently HOS test identified genetically balanced spermatozoa in chromosomal rearrangement carriers, with a 96% decrease in the proportion of unbalanced spermatozoa after selection. This may potentially improve reproductive prognosis in affected couples if used prior to pre-implantation genetic diagnosis (PGD).

HOS test is highly recommended for the male partners of couples who exhibit:

  • A history of unexplained infertility
  • Poor embryo quality after in vitro fertilization (IVF)
  • Implantation failure after IVF
  • Recurrent chemical or unexplained pregnancy losses, or 
  • Recurrent early spontaneous abortions 

We introduced the HOS test in 1984 to assess the functional integrity of the human sperm membrane and now it is accepted as a standard test to determine sperm quality. 


  • Interpretation of Semen Analysis Results: A Practical Guide by R.S.Jeyendran.
    Cambridge University Press, Cambridge, UK. 
  • Rouen A, Carlier L, Heide S, Egloff M, Marzin P, Ader F, Schwartz M, Rogers E, Joyé N, Balet R, Lédée N, Prat-Ellenberg L, Cassuto NG, Siffroi JP. Potential selection of genetically balanced spermatozoa based on the hypo-osmotic swelling test in chromosomal rearrangement carriers. Reprod Biomed Online. 2017 Oct;35(4):372-378.