title: Limitations in qualitative point of care hCG tests for detecting early pregnancy.
abstract: BACKGROUND
  Detection of early pregnancy in the healthcare setting is important for proper patient management. Qualitative point-of-care (POC) human chorionic gonadotropin (hCG) testing is often used. There is a gap in the literature for evaluating patient samples with low (<300 IU/l) hCG concentration using POC devices.
  
  
  METHODS
  Specimens (urine, n=289; serum, n=269) with hCG concentrations between 2 and >5000 IU/l were evaluated by hCG POC testing. Approximately half of these had an hCG concentration<300 IU/l. All specimens were evaluated using the OSOM and QuickVue+ POC hCG devices. Pregnancy status was evaluated by patient chart review.
  
  
  RESULTS
  The OSOM and QuickVue+ devices were able to detect hCG in 53% (OSOM) and 78% (QuickVue+) of urine samples with an hCG concentration range between 20 and 300 IU/l. Serum samples with an hCG concentration range between 10 and 300 IU/l gave positive results in 79 and 91% of samples tested using the OSOM and QuickVue+, respectively. False negative results could not be attributed to the high-dose hook effect, the hCG variant effect, or the interpreters' evaluation. The mean gestational age for specimens corresponding to the false negative results was 4 weeks.
  
  
  CONCLUSIONS
  The sensitivity of 2 commonly used hCG POC devices is insufficient for detecting very early pregnancy.
authors.affiliation: Kaiser Permanente, TPMG Northern California Regional Laboratory, Berkeley, CA, United States. dina.n.greene@kp.org
authors.forename: Dina N
authors.initials: DN
authors.lastname: Greene
authors.forename: Robert L
authors.initials: RL
authors.lastname: Schmidt
authors.forename: Sandy M
authors.initials: SM
authors.lastname: Kamer
authors.forename: David G
authors.initials: DG
authors.lastname: Grenache
authors.forename: Carolyn
authors.initials: C
authors.lastname: Hoke
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Lorey
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood* / Q000652:urine*; D005188:False Negative Reactions; D005260:Female; D005865:Gestational Age; D006801:Humans; D057230:Limit of Detection; D019095:Point-of-Care Systems; D011247:Pregnancy; D011258:Pregnancy Tests / Q000706:statistics & numerical data*; D011336:Probability; D012016:Reference Values
chemical_list: D006063:Chorionic Gonadotropin