Twelve studies were included in the review, of which five (with a total of 573 participants) reported sufficient data to calculate the accuracy of fibronectin. Three of these studies, which evaluated total fibronectin, were diagnostic cohorts and two, which evaluated cellular fibronectin, were matched case-controls. The studies reported multiple data sets for different gestation periods and fibronectin thresholds and fractions.
The quality assessment was based on 11 studies. All provided over 90% verification of diagnosis. Most of the studies provided an adequate description of the selection criteria, index test and reference standard. The studies were poorly compliant with other quality criteria; all were met by less than 50% of studies.
Where reported, the incidence of pre-eclampsia across all 12 studies ranged from 2.6 to 19.3%; in the studies reporting sufficient data to calculate accuracy, it ranged from 4.5 to 11.5%.
For cellular fibronectin (2 studies, 14 data sets), the sensitivity ranged from 50% (specificity 88% and 96%) to 100% (specificity 75%), and the specificity ranged from 72% (sensitivity 74%) to 96% (sensitivity 50%).
For total fibronectin (4 studies, 9 data sets), the sensitivity ranged from 50% (specificity 75%) to 83% (specificity 63%), and the specificity ranged from 43% (sensitivity 70%) to 94% (sensitivity 65%).