title: Total hCG tests.
abstract: BACKGROUND
  There are 12 types of automated total hCG tests sold today, the Abbott Architect, Abbott AxSym, the Beckman Access 2. Beckman DxI 800, the Ortho Vitros EciQ, Roche Elecsys hCG+β, Siemens ACS180, Siemens Centaur, Siemens Dimension, Siemens Immulite and Siemens Stratus, and the Tosoh A1A. All tests claim to be total hCG tests but do not define what total means. Total hCG test needs to detect all hCG variants in order to be used for all hCG test clinical applications. Here we assess this ability.
  
  
  METHODS
  Coded samples of pure hCG, nicked hCG, hyperglycosylated hCG, nicked hCG missing C-terminal peptide, nicked hyperglycosylated hCG, asialo hCG, hCGβ, nicked hCGβ and β-core fragment were tested blindly in serum and urine at 10 independent laboratories.
  
  
  RESULTS
  While the Siemens Immulite total hCG test detected 8 of 9 hCG variant standards, other assays poorly detected important determinants such as nicked hCG missing the C-terminal peptide, β-core fragment, hyperglycosylated hCG, nicked hCG, asialo hCG, and hCGβ. Four assay appropriately detected 4 of 9 variants, 2 assays detected 3 of 9, 4 assays detected 2 of 9 and 1 assay only appropriately detected 1 of 7 hCG variants.
  
  
  CONCLUSIONS
  Care is needed in selecting a total hCG test. The Siemens Immulite tests performed best at detecting all the hCG variants making it appropriate for all applications. Nine assays had limited applications, 3 of the assays were appropriate for advanced pregnancy testing only.
authors.affiliation: The USA hCG Reference Service, Women's Health Research, Department of Obstetrics and Gynecology, University of New Mexico, Albuquerque, NM 87131, USA. lac@unm.edu
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Cole
authors.forename: Stephen
authors.initials: S
authors.lastname: DuToit
authors.forename: Trefor N
authors.initials: TN
authors.lastname: Higgins
mesh_terms: D001331:Automation; D006063:Chorionic Gonadotropin / Q000032:analysis*; D019963:Clinical Chemistry Tests; D006801:Humans
chemical_list: D006063:Chorionic Gonadotropin