Validation of urinary Congo Red preeclampsia detection point-of-care devise

Abstract

Objectives

To evaluate a commercial a Congo Red urine devise for assessing preeclampsia risk.

Study design: Prospective non-intervention study among women presenting with clinical suspicion of preeclampsia. The devise was used at the time of enrolment and, depending on gestation, on 1–3 later occasions.

Outcome measures: Abnormal diffusion patterns classified as positive or negative, in relation to subsequent confirmation of preeclampsia (detection and false-positive rates, and predictive value) and the probability of diagnosis within a fixed time period (rule-in and rule-out).

Results

600 women were enrolled in the study and follow-up information was available on 538, of whom 95 had preeclampsia at delivery and 443 did not. At enrolment the detection rate was 18 % and the false-positive rate 3.2 %; positive predictive value – probability of positive result being associated with preeclampsia – was 55 % and negative predictive value – probability of negative result not being preeclampsia – was 85 %. A positive test ruled-in delivery with preeclampsia within 28 days among 35 % and ruled-out preeclampsia with 7 days among 98 %. Repeat testing after enrolment yielded similar results to the initial sample.

Conclusion

The test has screening potential although published studies differ in the observed detection rate. Using the test to rule-out preeclampsia within 7 days can provide a significant management advantage especially for triaging patients and selecting those who can be managed at the peripheral centres.