Through enabling whole blood detection in point-of-care testing (POCT), sedimentation-based plasma separation promises
to enhance the functionality and extend the application range of lateral flow assays (LFAs). To streamline the entire process
from the introduction of the blood sample to the generation of quantitative immune-fluorescence results, we combined a simple
plasma separation technique, an immunoreaction, and a micropump-driven external suction control system in a polymer
channel-based LFA. Our primary objective was to eliminate the reliance on sample-absorbing separation membranes, the use
of active separation forces commonly found in POCT, and ultimately allowing finger prick testing. Combining the principle
of agglutination of red blood cells with an on-device sedimentation-based separation, our device allows for the efficient and
fast separation of plasma from a 25-μL blood volume within a mere 10 min and overcomes limitations such as clogging,
analyte adsorption, and blood pre-dilution. To simplify this process, we stored the agglutination agent in a dried state on the
test and incorporated a filter trench to initiate sedimentation-based separation. The separated plasma was then moved to the
integrated mixing area, initiating the immunoreaction by rehydration of probe-specific fluorophore-conjugated antibodies. The
biotinylated immune complex was subsequently trapped in the streptavidin-rich detection zone and quantitatively analyzed
using a fluorescence microscope. Normalized to the centrifugation-based separation, our device demonstrated high separation
efficiency of 96% and a yield of 7.23 μL (= 72%). Furthermore, we elaborate on its user-friendly nature and demonstrate
its proof-of-concept through an all-dried ready-to-go NT-proBNP lateral flow immunoassay with clinical blood samples.