title: Qualitative point-of-care and over-the-counter urine hCG devices differentially detect the hCG variants of early pregnancy.
abstract: BACKGROUND
  Qualitative point-of-care (POC) tests for human chorionic gonadotropin (hCG) vary in their ability to detect purified hCG variants and there is data to suggest that over-the-counter (OTC) devices might also display similar variability. This could potentially influence the detection of urine hCG in early pregnancy.
  
  
  METHODS
  Six OTC devices were tested for their ability to detect 5 hCG variants. Ten early pregnancy urine specimens were selected for their diverse expression of hCG variants. The samples were tested with 6 brands of POC and 6 OTC devices.
  
  
  RESULTS
  OTC devices consistently recognized intact hCG, hCGn, and hCGbeta. hCGbetan was consistently recognized by 4 out of 6 brands. One brand inconsistently recognized hCGbetacf. OTC and POC devices varied greatly in their ability to detect hCG in early pregnancy urine, despite the fact that urine samples were adjusted to the same intact hCG concentration. Interestingly, we found that the OTC devices had better analytical sensitivity than the POC devices. Clinitest and First Response demonstrated the lowest hCG detection limits for POC and OTC devices, respectively.
  
  
  CONCLUSIONS
  Both OTC and POC devices are capable of detecting hCG concentrations in early pregnancy urine, and OTC devices demonstrated better analytical sensitivity relative to POC devices.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine St. Louis, MO 63110, United States.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Cervinski
authors.forename: Christina M
authors.initials: CM
authors.lastname: Lockwood
authors.forename: Angela M
authors.initials: AM
authors.lastname: Ferguson
authors.forename: Randall R
authors.initials: RR
authors.lastname: Odem
authors.forename: Ulf H
authors.initials: UH
authors.lastname: Stenman
authors.forename: Henrik
authors.initials: H
authors.lastname: Alfthan
authors.forename: David G
authors.initials: DG
authors.lastname: Grenache
authors.forename: Ann M
authors.initials: AM
authors.lastname: Gronowski
mesh_terms: D006063:Chorionic Gonadotropin / Q000652:urine*; D005260:Female; D006801:Humans; D019095:Point-of-Care Systems; D011247:Pregnancy; D013997:Time Factors; D016482:Urinalysis / Q000295:instrumentation* / Q000379:methods
chemical_list: D006063:Chorionic Gonadotropin