title: Home pregnancy test compared to standard-of-care ultrasound dating in the assessment of pregnancy duration.
abstract: OBJECTIVE
  To determine the level of agreement between the Clearblue Digital Pregnancy Test with Conception Indicator home pregnancy test and standard-of-care ultrasound in assessing pregnancy duration in a real-life, observational setting encompassing routine, clinical care.
  
  
  METHODS
  This was a prospective observational study of non-pregnant women seeking conception. Women collected daily urine samples from day 1 of their next menstrual cycle. If any volunteer became pregnant, daily urine samples continued to be collected for 43 days after the LH surge. Samples from day -7 to day +28 relative to the expected period (LH surge + 15 days) were tested using the home pregnancy test. This categorised any resulting pregnancies into one of three groups: 1-2 weeks, 2-3 weeks, and 3+ weeks since conception. Information from the standard UK ultrasound dating scan was also recorded by the midwife, including the expected delivery date according to ultrasound and the expected delivery date according to LMP.
  
  
  METHODS
  Full data were available from 52 pregnant women who had conceived naturally. During the study analysis, 4786 urine samples were cross-compared with 52 routine 12-week NHS ultrasound assessments and the level of agreement between home pregnancy testing and standard-of-care ultrasound in determining pregnancy duration was calculated.
  
  
  RESULTS
  The agreement between the gestational age as calculated by the home pregnancy test result and the exact midwife-recorded gestational age using ultrasound was 82.3%. However, when a ± 5-day range was applied to the ultrasound reading (as per routine UK clinical practice), the level of agreement was 98%.
  
  
  CONCLUSIONS
  The home pregnancy test provides a significantly high (98%) level of agreement with standard-of-care ultrasound when assessing pregnancy duration in a real-life, observational setting which closely mirrors daily clinical practice.
authors.affiliation: SPD Swiss Precision Diagnostics Development Company Limited, Bedford, UK. sarah.johnson@spdspark.com
authors.forename: S
authors.initials: S
authors.lastname: Johnson
authors.forename: R
authors.initials: R
authors.lastname: Shaw
authors.forename: P
authors.initials: P
authors.lastname: Parkinson
authors.forename: J
authors.initials: J
authors.lastname: Ellis
authors.forename: P
authors.initials: P
authors.lastname: Buchanan
authors.forename: M
authors.initials: M
authors.lastname: Zinaman
mesh_terms: D000328:Adult; D002910:Chronology as Topic; D005260:Female; D005865:Gestational Age; D006699:Home Care Services; D006801:Humans; D019370:Observation; D011247:Pregnancy; D011258:Pregnancy Tests / Q000295:instrumentation / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D012648:Self Care; D059039:Standard of Care; D016216:Ultrasonography, Prenatal / Q000379:methods* / Q000592:standards; D016482:Urinalysis / Q000295:instrumentation / Q000379:methods; D055815:Young Adult