title: Which Factors Contribute to False-Positive, False-Negative, and Invalid Results in Fetal Fibronectin Testing in Women with Symptoms of Preterm Labor?
abstract: ObjectiveWe assessed the influence of external factors on false-positive, false-negative, and invalid fibronectin results in the prediction of spontaneous delivery within 7 days.MethodsWe studied symptomatic women between 24 and 34 weeks' gestational age. We performed uni- and multivariable logistic regression to estimate the effect of external factors (vaginal soap, digital examination, transvaginal sonography, sexual intercourse, vaginal bleeding) on the risk of false-positive, false-negative, and invalid results, using spontaneous delivery within 7 days as the outcome.ResultsOut of 708 women, 237 (33%) had a false-positive result; none of the factors showed a significant association. Vaginal bleeding increased the proportion of positive fetal fibronectin (fFN) results, but was significantly associated with a lower risk of false-positive test results (odds ratio [OR], 0.22; 95% confidence intervals [CI], 0.12-0.39). Ten women (1%) had a false-negative result. None of the investigated factors was significantly associated with a significantly higher risk of false-negative results. Twenty-one tests (3%) were invalid; only vaginal bleeding showed a significant association (OR, 4.5; 95% CI, 1.7-12).ConclusionThe effect of external factors on the performance of qualitative fFN testing is limited, with vaginal bleeding as the only factor that reduces its validity.
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Merel M C
authors.initials: MM
authors.lastname: Bruijn
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Frederik J R
authors.initials: FJ
authors.lastname: Hermans
authors.affiliation: Department of Clinical Chemistry and Hematology, University Medical Centre Utrecht, The Netherlands.
authors.forename: Jolande Y
authors.initials: JY
authors.lastname: Vis
authors.affiliation: Department of Obstetrics and Gynecology, Catharina Hospital, Eindhoven, The Netherlands.
authors.forename: Femke F
authors.initials: FF
authors.lastname: Wilms
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Oudijk
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Anneke
authors.initials: A
authors.lastname: Kwee
authors.affiliation: Department of Obstetrics and Gynecology, Máxima Medical Centre, Veldhoven, The Netherlands.
authors.forename: Martina M
authors.initials: MM
authors.lastname: Porath
authors.affiliation: Department of Obstetrics and Gynecology, Máxima Medical Centre, Veldhoven, The Netherlands.
authors.forename: Guid
authors.initials: G
authors.lastname: Oei
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Maastricht, Maastricht, The Netherlands.
authors.forename: Hubertina C J
authors.initials: HC
authors.lastname: Scheepers
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Maastricht, Maastricht, The Netherlands.
authors.forename: Marc E A
authors.initials: ME
authors.lastname: Spaanderman
authors.affiliation: Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Kitty W M
authors.initials: KW
authors.lastname: Bloemenkamp
authors.affiliation: Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Monique C
authors.initials: MC
authors.lastname: Haak
authors.affiliation: Department of Obstetrics and Gynecology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Antoinette C
authors.initials: AC
authors.lastname: Bolte
authors.affiliation: Department of Obstetrics and Gynecology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Frank P H A
authors.initials: FP
authors.lastname: Vandenbussche
authors.affiliation: Department of Obstetrics and Gynecology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Mallory D
authors.initials: MD
authors.lastname: Woiski
authors.affiliation: Department of Obstetrics and Gynecology, VU University Medical Centre, Amsterdam, The Netherlands.
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Bax
authors.affiliation: Department of Obstetrics and Gynecology, Erasmus Medical Centre, Rotterdam, The Netherlands.
authors.forename: Jérôme M J
authors.initials: JM
authors.lastname: Cornette
authors.affiliation: Department of Obstetrics and Gynecology, Erasmus Medical Centre, Rotterdam, The Netherlands.
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Duvekot
authors.affiliation: Department of Obstetrics and Gynecology, Isala Clinics, Zwolle, The Netherlands.
authors.forename: Bas W A N I J
authors.initials: BW
authors.lastname: Bijvank
authors.affiliation: Department of Obstetrics and Gynecology, Isala Clinics, Zwolle, The Netherlands.
authors.forename: Jim
authors.initials: J
authors.lastname: van Eyck
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Centre Groningen, Groningen, The Netherlands.
authors.forename: Maureen T M
authors.initials: MT
authors.lastname: Franssen
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Centre Groningen, Groningen, The Netherlands.
authors.forename: Krystyna M
authors.initials: KM
authors.lastname: Sollie
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Joris A M
authors.initials: JA
authors.lastname: van der Post
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Patrick M M
authors.initials: PM
authors.lastname: Bossuyt
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Marjolein
authors.initials: M
authors.lastname: Kok
authors.affiliation: The Robinson Research Institute School of Medicine, University of Adelaide and The South Australian Health and Medical Research Institute Adelaide Australia, Adelaide, SA, Australia.
authors.forename: Ben W J
authors.initials: BW
authors.lastname: Mol
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: van Baaren
mesh_terms: D000328:Adult; D003075:Coitus; D019160:Endosonography; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D005353:Fibronectins / Q000032:analysis*; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000175:diagnosis* / Q000378:metabolism; D011247:Pregnancy; D012307:Risk Factors; D012915:Soaps; D014592:Uterine Hemorrhage / Q000378:metabolism; D014621:Vagina / Q000737:chemistry*; D055815:Young Adult
chemical_list: C403421:FFN protein, human; D005353:Fibronectins; D012915:Soaps