Am J Perinatol 2017; 34(03): 234-239
DOI: 10.1055/s-0036-1585466
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Which Factors Contribute to False-Positive, False-Negative, and Invalid Results in Fetal Fibronectin Testing in Women with Symptoms of Preterm Labor?

Merel M.C. Bruijn
1   Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
,
Frederik J.R. Hermans
1   Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
,
Jolande Y. Vis
2   Department of Clinical Chemistry and Hematology, University Medical Centre Utrecht, The Netherlands
,
Femke F. Wilms
3   Department of Obstetrics and Gynecology, Catharina Hospital, Eindhoven, The Netherlands
,
Martijn A. Oudijk
1   Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
,
Anneke Kwee
4   Department of Obstetrics and Gynecology, University Medical Centre Utrecht, Utrecht, The Netherlands
,
Martina M. Porath
5   Department of Obstetrics and Gynecology, Máxima Medical Centre, Veldhoven, The Netherlands
,
Guid Oei
5   Department of Obstetrics and Gynecology, Máxima Medical Centre, Veldhoven, The Netherlands
,
Hubertina C.J. Scheepers
6   Department of Obstetrics and Gynecology, University Hospital Maastricht, Maastricht, The Netherlands
,
Marc E.A. Spaanderman
6   Department of Obstetrics and Gynecology, University Hospital Maastricht, Maastricht, The Netherlands
,
Kitty W.M. Bloemenkamp
7   Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands
,
Monique C. Haak
7   Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands
,
Antoinette C. Bolte
8   Department of Obstetrics and Gynecology, Radboud University Medical Centre, Nijmegen, The Netherlands
,
Frank P.H.A. Vandenbussche
8   Department of Obstetrics and Gynecology, Radboud University Medical Centre, Nijmegen, The Netherlands
,
Mallory D. Woiski
8   Department of Obstetrics and Gynecology, Radboud University Medical Centre, Nijmegen, The Netherlands
,
Caroline J. Bax
9   Department of Obstetrics and Gynecology, VU University Medical Centre, Amsterdam, The Netherlands
,
Jérôme M.J. Cornette
10   Department of Obstetrics and Gynecology, Erasmus Medical Centre, Rotterdam, The Netherlands
,
Johannes J. Duvekot
10   Department of Obstetrics and Gynecology, Erasmus Medical Centre, Rotterdam, The Netherlands
,
Bas W.A.N.I.J. Bijvank
11   Department of Obstetrics and Gynecology, Isala Clinics, Zwolle, The Netherlands
,
Jim van Eyck
11   Department of Obstetrics and Gynecology, Isala Clinics, Zwolle, The Netherlands
,
Maureen T.M. Franssen
12   Department of Obstetrics and Gynecology, University Medical Centre Groningen, Groningen, The Netherlands
,
Krystyna M. Sollie
12   Department of Obstetrics and Gynecology, University Medical Centre Groningen, Groningen, The Netherlands
,
Joris A.M. van der Post
1   Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
,
Patrick M.M. Bossuyt
13   Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, Amsterdam, The Netherlands
,
Marjolein Kok
1   Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
,
Ben W.J. Mol
14   The Robinson Research Institute School of Medicine, University of Adelaide and The South Australian Health and Medical Research Institute Adelaide Australia, Adelaide, SA, Australia
,
Gert-Jan van Baaren
1   Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
› Author Affiliations
Further Information

Publication History

12 February 2016

09 June 2016

Publication Date:
21 July 2016 (online)

Abstract

Objective We assessed the influence of external factors on false-positive, false-negative, and invalid fibronectin results in the prediction of spontaneous delivery within 7 days.

Methods We 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.

Results Out 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).

Conclusion The effect of external factors on the performance of qualitative fFN testing is limited, with vaginal bleeding as the only factor that reduces its validity.

 
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