Finalist: Utilizing Optical Interrogation Methods for Early Diagnosis of Peritonitis in Peritoneal Dialysis Patients

In the United States, over 26,500 patients use peritoneal dialysis (PD) each year and are at risk for developing peritonitis, an infection of the peritoneum that causes scarring and thus prevents the peritoneum from serving as an efficient exchange membrane during PD. Patients then have to switch from the gentler and more convenient method of PD to hemodialysis (HD). While PD utilizes an at-home setup, HD requires multiple visits to dialysis centers, which is both inconvenient and expensive -- healthcare, dialysis center, and hospitalization costs sum to over double that of PD. The current standard of care for detecting peritonitis involves the patient first self-reporting their symptoms and then sending in their dialysis waste for a white blood cell (WBC) test and bacterial culture, which can take up to 8 days. Untreated infection puts the patient at risk for developing peritonitis, inflammation of the peritoneum, and other possible complications.

Our team aims to design a way to detect peritonitis before patient awareness for those who are using PD in order to treat the infection earlier. This will reduce acute hospitalization costs and prevent scarring of the peritoneum, therefore improving PD longevity . Our solution, the OpticLine, seamlessly integrates within the current PD setup, connecting in series with the drain lines used. The OpticLine will use spectrophotometry to analyze the optical density (OD) of WBCs in the dialysis waste fluid as a way to gauge for infection.

Using our works-like spectrophotometer prototype, we measured various WBC concentrations in Dulbecco's phosphate-buffered saline (DPBS). Our results from our works-like spectrophotometer prototype experiment indicate that we detect a significant difference in optical density between our two WBC concentrations of interest: 10 WBC/mm 3 (normal) and 1000 WBC/mm 3 (infected) (p-value = 1.47E-07).

Submitted by Mark Buckup, Alisha Birk, and Janelle Kaneda on behalf of the Stanford University Bioengineering Department.

Learn more by contacting OpticLine at jam.opticline@gmail.com.