title: Analytical sensitivity of four commonly used hCG point of care devices.
abstract: BACKGROUND
  Point of care (POC) hCG assays are often used to rule-out pregnancy and therefore diagnostic sensitivity, especially at low concentrations of hCG, is important. There are very few studies in the literature that seek to verify the claimed analytical sensitivity of hCG POC devices.
  
  
  METHODS
  The analytical sensitivity of four commonly used hCG POC devices (Alere hCG Combo Cassette, ICON 20 hCG, OSOM hCG Combo Test, and Sure-Vue Serum/Urine hCG-STAT) was challenged using urine samples (n=50) selected based on quantitative hCG concentrations. The majority of these specimens (n=40) had an hCG concentration between 20 and 200 U/L. Each specimen/device combination was reviewed by three individuals. Statistical calculations were performed using Stata 12.
  
  
  RESULTS
  The analytical sensitivity of the OSOM was significantly lower inferior than that of the other POC devices. There was no significant difference in the sensitivity of the Alere, ICON 20 and Sure-Vue devices. There was no significant difference in the individual interpretation of the hCG POC results.
  
  
  CONCLUSIONS
  All hCG POC devices evaluated in this study were susceptible to false negative results at low concentrations of urine hCG. Laboratorians and clinicians should be aware that there are limitations when using urine hCG POC devices to rule out early pregnancy.
authors.affiliation: Kaiser Permanente, TPMG Northern California Regional Laboratory, Berkeley, CA, USA.
authors.forename: Sandy M
authors.initials: SM
authors.lastname: Kamer
authors.affiliation: Kaiser Permanente Northwest, Portland, OR, USA.
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Foley
authors.affiliation: University of Utah School of Medicine, Department of Pathology, Salt Lake City, UT, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Schmidt
authors.affiliation: Kaiser Permanente, TPMG Northern California Regional Laboratory, Berkeley, CA, USA. Electronic address: dngreene@uw.edu.
authors.forename: Dina N
authors.initials: DN
authors.lastname: Greene
mesh_terms: D006063:Chorionic Gonadotropin / Q000652:urine*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D019095:Point-of-Care Systems; D011247:Pregnancy; D011258:Pregnancy Tests / Q000592:standards*; D012372:ROC Curve
chemical_list: D006063:Chorionic Gonadotropin
keywords: Analytical sensitivity; False negative; Human chorionic gonadotropin (hCG); Limit of detection; Point of care (POC)