MUL+DO: a multicomponent index for the quick diagnosis of peritonitis in peritoneal dialysis patients

Peritoneal infection is a common problem that has a negative impact on the survival of patients and the technique. The early administration of peritoneal infection treatment reduces complications. The goal of this study is to propose a multicomponent index (MUL+DO) for the quick and efficient diagnosis of peritoneal infection. We selected a training cohort of peritoneal effluent samples which were analysed by Multistix ® 10 SG Siemens test strips for leukocyte detection. Then, each sample was examined according to the gold standard: number of leukocytes, polymorphonuclear percentage and microbiological culture. We constructed the MUL+DO index by adding one point to the MULTISTIX [0-1-2-3] modified chromatic scale if the patient reported pain. The MUL+DO index ranged from 0 to 4. A model validation cohort was then created. MUL+DO was applied to each sample and leukocytes and polymorphonuclear percentage were also assessed. The training cohort ultimately included 134 samples, 34 of which with infection (25.4% [17.6-33.1]). Samples with a MUL+DO value greater than 1 presented a sensitivity and specificity of 100%. The validation cohort included 100 samples with 16 infections (16% [8.3-23.7]). Assuming a sample with a MUL+DO value greater than 1 to be positive, we obtained a sensitivity of 100% and a specificity of 95.2%. The MUL+DO index applied to the training cohort showed a perfect separation of the positive and negative populations. All positive patients presented a score ≥2. In the validation cohort, the MUL+DO reported a sensitivity of 100% and a specificity of 95.2%.