Ultra-Rapid β2-Transferrin Lateral Flow Immunoassay Enables Accurate Point-of-Care Detection of Cerebrospinal Fluid

BACKGROUND AND OBJECTIVES: Cerebrospinal fluid (CSF) leak diagnosis often relies on laboratory β2-transferrin testing, which is specific but not optimized for immediate bedside decision making. We air to evaluate a rapid β2-transferrin lateral flow immunoassay (LFIA) for point-of-care CSF detection. METHODS: Human CSF samples were obtained from adult patients with external ventricular drains and tested using a blinded, standardized LFA protocol. Sterile saline and non-CSF drain fluid served as negative controls. Selected CSF samples underwent 1:10 and 1:100 saline dilution. Results were classified as positive, negative, or invalid/inconclusive and summarized descriptively. RESULTS: A total of 399 assay runs were included. Raw CSF was positive in 232 of 232 tests. CSF:saline 1:10 samples were positive in 23 of 25 tests, with 2 invalid/inconclusive results, and CSF:saline 1:100 samples were positive in 20 of 20 tests. Saline controls showed 0 positive results in 98 tests. Drain-fluid controls showed 0 positive results in 24 tests, with 23 negative and 1 invalid/inconclusive result. Among cassette-positive samples with valid timing, the median time to positivity was 14.0 minutes for raw CSF, 5.0 minutes for 1:10 CSF:saline, and 8.6 minutes for 1:100 CSF:saline. CONCLUSION: This feasibility study supports the potential utility of a rapid β2-transferrin LFA as a simple point-of-care assay for CSF detection. Larger prospective validation in real-world rhinorrhea, otorrhea, wound-drainage, and postoperative leak samples is warranted.