title: Measuring human chorionic gonadotropin in the absence of implantation with use of highly sensitive urinary assays for intact beta-core and free beta epitopes.
abstract: OBJECTIVE
  To determine if human chorionic gonadotropin (hCG) can be absorbed from the uterine cavity in the absence of an embryo.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  University-based assisted reproduction program.
  
  
  METHODS
  Eight functionally agonadal patients (age range, 33-46 years) who were taking hormone replacement therapy so that they could receive donated oocytes.
  
  
  METHODS
  Intrauterine instillation of 50 microL of hCG (10,000 IU) during a mock cycle before an attempt at oocyte donation.
  
  
  METHODS
  Spot urine measurements of different hCG epitopes (intact beta, beta-core, and free beta) at timed intervals (12, 20, 44, and 68 hours after instillation).
  
  
  RESULTS
  All hCG epitopes were detected in the urine at the first sampling interval, and levels decreased in subsequent sampling intervals. Measurement of the serum hCG level confirmed that systemic absorption had occurred and that the urine measurements were not a result of specimen contamination through the cervix.
  
  
  CONCLUSIONS
  hCG may be systemically absorbed into the blood through the uterine cavity, even in the absence of implantation, and its metabolites may be measured with use of highly sensitive urinary assays.
authors.affiliation: Department of Obstetrics and Gynecology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Chang
authors.forename: R E
authors.initials: RE
authors.lastname: Canfield
authors.forename: E C
authors.initials: EC
authors.lastname: Ditkoff
authors.forename: J F
authors.initials: JF
authors.lastname: O'Connor
authors.forename: M V
authors.initials: MV
authors.lastname: Sauer
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood / Q000652:urine*; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000652:urine; D010064:Embryo Implantation; D004624:Embryo Transfer; D000939:Epitopes / Q000652:urine; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D015592:Immunoradiometric Assay; D008875:Middle Aged; D018587:Oocyte Donation; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D000939:Epitopes