title: Accuracy of soluble human leukocyte antigen-G for predicting pregnancy among women undergoing infertility treatment: meta-analysis.
abstract: BACKGROUND
  There have been concerns about validity and accuracy of the measurement of sHLA-G in embryo culture supernatants. In this systematic review, we quantified the diagnostic accuracy of sHLA-G for predicting the ability to achieve clinical pregnancy in women who are undergoing infertility treatment.
  
  
  METHODS
  Medline and Embase were searched up to 7 September 2007, for full English and non-English articles concerning cohort studies evaluating sHLA-G in embryo culture for predicting clinical pregnancy in women undergoing IVF and ICSI.
  
  
  RESULTS
  Eleven studies including 1813 patients met our inclusion criteria. In the individual studies, sensitivity ranged from 0.01 to 0.97, specificity from 0.18 to 0.98, the positive likelihood ratio from 0.34 to 3.21 and the negative likelihood ratio from 0.08 to 1.01. These values were highly heterogeneous with, in each case, I(2) values of >75%, and P-values for the Q statistic of <0.001, arguing against generating a pooled estimate for these diagnostic test properties. The diagnostic odds ratios (DORs) ranged from 0.92 to 24.82 in the individual studies with an I(2) value of 49% indicating moderate heterogeneity. Therefore, the meta-analysis combined the logs of the DORs, which are derived from sensitivity and specificity. A random-effects model yielded a summary DOR of 4.38 (95% CI, 2.93-6.55), consistent with modest diagnostic accuracy. Interestingly, an a priori defined subgroup analysis restricted to six studies with good quality embryos showed a better diagnostic performance with a DOR of 12.67 (95% CI, 3.66-43.80) to predict the ability to achieve clinical pregnancy in women undergoing infertility treatment.
  
  
  CONCLUSIONS
  Further research is needed with single-embryo culture, single-embryo transfer and highly sensitive detection techniques to determine the potential application of measuring sHLA-G in culture supernatant.
authors.affiliation: Laboratory of Haematology, Universitair Ziekenhuis Brussel (UZ Brussel), Laarbeeklaan 101, B-1090, Brussels, Belgium.
authors.forename: M J
authors.initials: MJ
authors.lastname: Vercammen
authors.forename: A
authors.initials: A
authors.lastname: Verloes
authors.forename: H
authors.initials: H
authors.lastname: Van de Velde
authors.forename: P
authors.initials: P
authors.lastname: Haentjens
mesh_terms: D046149:Embryo Culture Techniques; D005260:Female; D005307:Fertilization in Vitro; D006680:HLA Antigens / Q000032:analysis*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D006801:Humans; D007246:Infertility / Q000628:therapy*; D011237:Predictive Value of Tests; D011247:Pregnancy; D012680:Sensitivity and Specificity; D020554:Sperm Injections, Intracytoplasmic
chemical_list: D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I