Late pregnancy screening for preeclampsia with a urinary point-of-care test for misfolded proteins

Abstract

The aim was to describe and assess a new late pregnancy point-of-care urinary preeclampsia screening test. Urine samples were collected from a consecutive series of 1,532 pregnant women hospitalized at 20-41 weeks gestation in a Chinese single obstetric unit. A simple disposable Congo red based device was newly developed and employed to prospectively test misfolded proteins in pregnant women's urine. A total of 140 preeclampsia cases were clinically diagnosed, 101 severe and 87 pre-term. Detection and false positive rates were similar in the training and validation subsets with combined 74% and 3.0%. The detection rate was 83% in severe, 86% in pre-term, 49% and 50% in mild and term cases (P<0.0001) respectively. In conclusion, a simple point-of-care urinary test for misfolded proteins can be used to screen for preeclampsia in late pregnancy with very high screening performance. To the best of our knowledge, this is the first study to screen for preeclampsia using Congo red based device in Chinese pregnant population.

Screening for late preeclampsia at 35–37 weeks by the urinary Congo-red dot paper test

“…Most previous studies investigated urinary Congo-red dye positivity as a diagnostic test in pregnancies with established disease and reported a high performance in distinguishing between PE and unaffected pregnancies [13][14][15][16][17][18]. There is only one previous study that investigated the value of urinary Congo-red dye positivity in the prediction of subsequent development of the disease; screening at 11-13 weeks' gestation provided poor prediction of PE [15].…”

“…Two previous studies used a paper-based point-ofcare test to diagnose PE within a few minutes of testing [17,18]. Rood et al evaluated for PE 346 consecutive pregnant women who presented to a triage unit; PE was confirmed in 96 cases and the detection rate and false positive rates of Congo-red dye test were 80% and 11%, respectively [17].…”

“…Rood et al evaluated for PE 346 consecutive pregnant women who presented to a triage unit; PE was confirmed in 96 cases and the detection rate and false positive rates of Congo-red dye test were 80% and 11%, respectively [17]. Li et al evaluated 1532 pregnant women hospitalized at 20-41 weeks' gestation; PE was diagnosed in 140 cases and the detection rate of preterm and term PE and false positive rates of the Congo-red dye test were 86%, 50%, and 3%, respectively [18]. In contrast to these two studies, we investigated pregnancies before the development of PE and found the predictive performance of the test to be very poor.…”

“…There is some evidence that a potentially useful biomarker for the diagnosis and prediction of PE may be urinary Congo-red dye positivity, which indicates the presence of amyloid protein, an aggregate of misfolded proteins [13][14][15][16][17][18]. Several cross-sectional studies have investigated the incidence of urinary Congo-red dye positivity in women with PE, compared to unaffected pregnancies, and reported very high sensitivity and low false positive rate in the diagnosis of PE [13][14][15][16].…”

“…Congo-red dye positivity was observed in 33%, 16%, and 20% of cases of early PE, late PE, and unaffected pregnancies, respectively. Initial studies for assessment of Congo-red dye positivity necessitated a laboratory based analysis, but more recently a simple point-ofcare test that provides results within a few minutes of testing was introduced [17,18].…”