For over 20 years BioDot has been manufacturing equipment for the production of Flow Through Diagnostic Devices.
Flow Through and Lateral Flow diagnostic devices use membranes as the active media on which the relative biomarkers are printed and the assay is executed.
In Flow Through devices, reagents and samples flow normally to the membrane, and the conjugate is added in a liquid format after being mixed with the sample and buffers. An absorbing pad sits under the membrane.
In Lateral Flow devices, reagents and samples flow parallel and within the membrane, and the absorbing pad sits at the end of the membrane flow path.
The assembly and development methods are different for each type of device. The original concept for Lateral Flow was to incorporate the conjugate in a dry format on a separate pad along the membrane flow path. This has changed with the use of new test strip designs in Lateral Flow devices that add the conjugate in a liquid format mixed with the sample. This is done for several reasons, one being improved performance.
The Flow Through devices use a dot format for the test and control reagents, while Lateral Flow devices use line formats. The normal flow and spot formats used in the Flow Through device have historically led to much lower Coefficient of Variance (CVs) than for Lateral Flow, making the Flow Through technology a quantitative device when used with a reader.