title: Sperm creatine phosphokinase M-isoform ratios and fertilizing potential of men: a blinded study of 84 couples treated with in vitro fertilization.
abstract: OBJECTIVE
  To examine the value of sperm creatine phosphokinase M-isoform (CK-MM) measurements toward predicting fertilizing potential of men.
  
  
  METHODS
  In 84 in vitro fertilization (IVF) couples without knowing the semen parameters, reproductive history or the outcome of the IVF cycles, we determined the sperm CK-MM ratios (the proportion of sperm CK-MM versus CK-MM+CK-BB). Husbands with less than 10% or greater than or equal to 10% CK-MM ratios were classified as "low likelihood for fertilization" (CKMM-Infertile, n = 22) or "high likelihood for fertilization" (CKMM-Fertile, n = 62), respectively.
  
  
  RESULTS
  Both the CKMM-Infertile and CKMM-Fertile groups (CK-MM ratios: 4.9% +/- 0.6% versus 31.1% +/- 1.8%) were in the normospermic range (31.5 +/- 6.9 versus 78.4 +/- 5.9 x 10(6) sperm/mL and 45.6% +/- 5.0% versus 54.0% +/- 2.0% motility). The fertilization rates (6.2 versus 4.9 oocytes inseminated) were 14.2% versus 53.4%, and 72.7% versus 25.8% of the couples failed to achieve any oocyte fertilization. All 14 pregnancies (16.7% rate) occurred in the CKMM-Fertile group. The pregnancy rate in the 62 CKMM-Fertile couples was 22.6%, and considering only the 46 CKMM-Fertile women in whom oocyte fertilization occurred, it was 30.4%. Among the 22 CKMM-Infertile men, 9 were normospermic and 9 of the 62 CKMM-Fertile men were oligospermic. Within the CKMM-Fertile group, 12 and 2 of the 14 pregnancies occurred by the 53 normospermic and 9 oligospermic men (22.6% versus 22.2% rate).
  
  
  CONCLUSIONS
  Sperm CK-MM ratios, a measure of normal sperm development, predict fertilizing potential independently from sperm concentrations. Sperm CK-MM ratios also detect unexplained male infertility (infertile men with normospermic semen), a diagnosis that until now could not be substantiated.
authors.affiliation: Yale University School of Medicine, New Haven, Connecticut 06510-8063.
authors.forename: G
authors.initials: G
authors.lastname: Huszar
authors.forename: L
authors.initials: L
authors.lastname: Vigue
authors.forename: M
authors.initials: M
authors.lastname: Morshedi
mesh_terms: D015415:Biomarkers; D003402:Creatine Kinase / Q000032:analysis*; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology; D007527:Isoenzymes; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D012107:Research Design; D013094:Spermatozoa / Q000201:enzymology / Q000502:physiology*
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D003402:Creatine Kinase