How a sandwich lateral flow strip reads a blood biomarker
One run shown twice at the same instant. The cross-section shows what the molecules are doing inside the pads. The top view shows what you see through the cassette.
0:00Assay clock, illustrative
Sample + target
→
Target carries the label to the test line
labeled antibodiesTestControl
Key
Red blood cellHeld back by the RBC filter at the well
Capture antibody, T lineFixed in the membrane, binds the biomarker
Anti-IgG antibody, C lineBinds the detection antibody itself
Plasma, then chase bufferThe buffer pushes the small plasma volume along
Schematic, not to scale. Molecules are drawn thousands of times larger than the pads, and the vertical axis of the cross-section is stretched. Timings vary by product; many tests are read at 10 to 15 minutes.