582: Congo red dot test quantkit: a smartphone application to measure congophilia in the urine of women screened for preeclampsia (PE)

Aberrant protein misfolding and aggregation are two recently discovered molecular signatures of PE. Congo Red dye adheres to misfolded urinary proteins of preeclamptic women, a characteristic known as congophilia. This has led to the development of the Congo Red Dot Test (CRD) Quantkit, which can provide an unbiased and accurate diagnostic test for PE. Development of a smartphone application that can enable quantitative point of care assessment of urine congophilia in women at risk carries the potential of a major breakthrough in obstetrics. A smartphone camera was used to take images of the point of care CRD test results, performed on crude urine (n=40). Images were then blindly analyzed using a mobile phone application developed by our team. Optimal specimen renditions such as alignment, cropping, and perspective correction were applied to images. An algorithm was used to eliminate illumination gradients, segment the red and blue channels and calculate the area ratio of the test result (Figure). Results from the mobile application were compared to the laboratory derived CRD Test results (a benchside quantitative measure of the % of Congo Red retention [CRR] on protein-normalized urine). The result of the smartphone application correlated with the CRR (r=0.833, P<.001). The algorithm demonstrated an area ratio of ≤0.17 when the CRR was ≤15% (no-PE) in all our control patients (n=21). An area ratio of >0.5 was seen with a CRR >15%[35.4-130.4] (yes-PE) in 74% (n=14) of women with PE. Ratios between 0.1 and 0.36 with CRR >15%[16.3-73.3] were identified in 5 women, clinically classified as sPE, implying that further evaluation is necessary for a ratio <0.5. The use of an unbiased, cost-effective mobile application for immediate interpretation of the CRD Test Quantkit has major clinical translation character and the potential to improve diagnosis of PE in resource limited settings.