Lateral Flow Assays

Because of their low cost, reliability, and ease of use, lateral flow test strips (LFTS) have become commercially successful. In current applications such as pregnancy tests, LFTS are limited to a single-biomarker measurement, and the reading is usually qualitative. Large coefficients of variation (CV), high false positives and false negatives, and a narrow dynamic range have also limited the effectiveness of many of these assays.

In the lateral flow assay (LFA) research program at Intelligent Optical Systems (IOS), the focus is on addressing the need for simultaneous measurement of multiple biomarkers from clinical samples to aid in the prognosis, diagnosis, and treatment of a number of conditions, including traumatic brain injury (TBI), ovarian cancer, cardiac events, bone metabolism, and infectious diseases such as leishmaniasis. Traditional LFTS have been modified by incorporating reliable labeling techniques that improve the stability, sensitivity, and repeatability of the assay, resulting in semi-quantitative rapid screening in point-of care (POC) settings or field applications. The use of multiple biomarkers on a single test strip and the development of algorithms that can correlate the results from distinct biomarkers can significantly enhance the accuracy of the reading over that of a single biomarker.

We have established the feasibility of our multiplexed LFTS approach by measuring multiple biomarkers in TBI, ovarian cancer, cardiac, and Leishmania samples. Tests conducted with clinical samples were validated by comparing the results with those from enzyme linked immunosorbent assay (ELISA) measurements, demonstrating that LFTS assays can measure biomarkers at clinical concentrations relevant to clinical practice.