title: The predictive fertilization value of the hypoosmotic swelling test (HOST) for fresh and cryopreserved sperm.
abstract: BACKGROUND
  The hypoosmotic swelling test (HOST) was recommended as a predictive test for in vitro fertilization (IVF) outcome. These results, however, were controversial and the results for thawed semen were insufficient. The present study was conducted in order to clarify the predictive value of the HOST for IVF in fresh and thawed sperm.
  
  
  METHODS
  The hypoosmotic swelling test was performed in three groups: husband's fresh semen "subfertile" group, donor's thawed semen group, and donor's fresh semen "fertile" group.
  
  
  RESULTS
  No correlation was found between HOST values and sperm characteristics in fresh or thawed sperm. Fresh sperm HOST values correlated with IVF fertilizations. No such correlations were found when thawed sperm was used. HOST values were significantly higher in the fresh fertile donor group than in the fresh subfertile group (P less than 0.001). Following the freezing and thawing process, HOST values decreased dramatically. Nevertheless, the fertilization rate was still higher compared to that of the fresh subfertile group (P less than 0.001). There were significantly more IVF cycles with no fertilizations when HOST values were below 45%.
  
  
  CONCLUSIONS
  The HOST has a predictive value for fertilization of oocytes in IVF cycles when fresh semen, but not thawed sperm, is used. The freezing-thawing process affects the outer membrane of the spermatozoon and changes its characteristics, leading to a decrease in HOST values. Sperm characteristics that play a role in the fertilization process are not expressed directly by HOST values.
authors.affiliation: Institute for the Study of Fertility, Tel Aviv Sourasky Medical Center, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Hauser
authors.forename: H
authors.initials: H
authors.lastname: Yavetz
authors.forename: G F
authors.initials: GF
authors.lastname: Paz
authors.forename: Z T
authors.initials: ZT
authors.lastname: Homonnai
authors.forename: A
authors.initials: A
authors.lastname: Amit
authors.forename: J B
authors.initials: JB
authors.lastname: Lessing
authors.forename: M R
authors.initials: MR
authors.lastname: Peyser
authors.forename: L
authors.initials: L
authors.lastname: Yogev
mesh_terms: D002462:Cell Membrane / Q000502:physiology; D015925:Cryopreservation; D004624:Embryo Transfer; D005307:Fertilization in Vitro; D006801:Humans; D007317:Insemination, Artificial, Homologous; D008297:Male; D009997:Osmotic Pressure; D010062:Ovulation Induction / Q000379:methods; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013094:Spermatozoa / Q000502:physiology*; D014019:Tissue Donors