Study of a Semi-quantitative Lateral Flow Immunoassay for Procalcitonin Detection in Postpartum Sepsis Diagnosis

Introduction Sepsis represents a significant global health challenge, causing millions of deaths annually and highlighting the urgent need for rapid diagnostic tools. This study evaluated the performance of a semi-quantitative lateral flow immunoassay (LFIA) for procalcitonin (PCT) detection in postpartum sepsis diagnosis, addressing the critical need for point-of-care testing (POCT) in resource-limited settings. Methods A prospective, single-center validation study was conducted with 59 postpartum women enrolled from routine postpartum checkups. The study population included 25 healthy controls, 20 postpartum women without sepsis, and 14 with confirmed sepsis. All participants underwent PCT testing using both the semi-quantitative LFIA and reference enzyme-linked immunosorbent assay (ELISA) methods. Analytical performance parameters, including sensitivity, specificity, precision, and clinical correlation, were evaluated. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal cut-off values. Results The PCT LFIA demonstrated excellent diagnostic performance with a sensitivity of 96.2% (95% CI: 88.2%-99.4%) and a specificity of 98.1% (95% CI: 87.5%-99.8%) at a cut-off of 0.5 ng/mL. The assay showed strong correlation with reference ELISA methods (r > 0.97) and maintained precision with an intra-assay coefficient of variation (CV) ranging from 3.2% to 6.5% and inter-assay variation from 4.6% to 8.9%. The limit of detection (LoD) was 0.5 ng/mL with a limit of quantification (LoQ) of 1.0 ng/mL. Postpartum women with sepsis showed significantly elevated PCT levels compared to healthy controls and those without sepsis. Conclusion The semi-quantitative PCT LFIA offers a promising, cost-effective tool for rapid sepsis diagnosis in postpartum women. The assay's high sensitivity and specificity, combined with its point-of-care applicability, make it particularly valuable for improving maternal health outcomes in resource-limited settings where timely sepsis diagnosis is crucial.