A new optical immunoassay for detection of S-100B protein in whole blood

Background. S-100B is a protein mainly found in astroglial cells and only detected to a low level in blood. Serum levels of S-100B increase in patients with acute brain injuries. The aim of this study was to establish feasibility of a new Optical ImmunoAssay ([OIA], BioStar, Inc, Boulder, CO) test for determination of S-100B in blood. Methods. We have developed a new, rapid, and sensitive OIA test to identify elevated levels of S-100B in whole blood. The OIA test for S-100B combines monoclonal antibodies specific for the B-subunit of S-100 with OIA thin film technology. Each sample was tested for S-100B by the OIA method and a commercially available immunoluminometric assay. Blood samples were drawn serially from 9 patients undergoing coronary artery bypass graft surgery and during the early postoperative period. Results. The OIA test determination of S-100B protein correlated with immunoluminometric assay data (r = 0.8) with a detection limit of 0.25 ng/mL. Conclusions. The sensitivity and feasibility of this rapid assay may be suitable for rapid evaluation of S-100B in urgent care settings (surgery, intensive care units, or emergency room).