Diagnostic Performance of Point-of-Care Immunoassay Measurements of Pancreatic Stone Protein for Sepsis Detection in ICU Patients: A Prospective, Multicenter, Biomarker-Blinded Study

Objectives: To evaluate the diagnostic performance of a rapid point-of-care immunoassay measuring pancreatic stone protein (PSP) for early sepsis identification within the first three days of ICU admission. Subgroup analyses (sex, age, febrile status) were conducted, and the combined diagnostic value of PSP and C-reactive protein (CRP) was assessed. Design: Multicenter, prospective, observational study. Patient: Four hundred sixty-six adults the ICU. Setting: Six ICUs in the United States who were expected to required at least 24 hours of ICU care. Interventions: None. Measurements and Main Results: We calculated the Youden Index to evaluate the clinical performance of the PSP assay, and the resulting threshold was used to identify patients with sepsis. Diagnostic performance metrics included sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR–). Receiver operating characteristic analysis were performed for PSP and CRP. At the optimal PSP cutoff point of 117 ng/mL, PSP demonstrated a sensitivity of 74.2%, specificity of 67.8%, accuracy of 71.0%, PPV of 70.3%, NPV of 71.9%, and LR+ and LR– ratios of 2.30 and 0.38, respectively. Combining PSP and CRP improved diagnostic specificity to 95.2%. Subgroup analyses demonstrated consistent performance across sex, and higher specificity was observed in patients 18–60 years old. In febrile patients, PSP achieved high specificity (87.5%) but lower sensitivity (63.6%). In non-febrile patients, sensitivity and specificity were 67.7% and 76.6%, respectively. Conclusions: PSP can serve as a biomarker for the early identification of sepsis. Diagnostic performance across diverse ages, sex, and clinical presentation supports the assay’s broad applicability. The combination of PSP and CRP enhances diagnostic specificity for sepsis detection, offering a complementary approach to improve sepsis detection and lead to earlier appropriate management.