Behind the scenes

Taking a lateral flow device apart reveals that quality is more than skin deep.

At first glance a lateral flow device appears to be a simple plastic object with some sort of membrane inside on which a reaction takes place.. You have probably not given it any more thought than that.  But in reality, a Pocket Diagnostic test is a product manufactured to high standards on the latest in high-tech automated equipment.  In this article we take a brief look at how the tests are produced, and how this contributes to their reliable performance.

Manufacturing for quality

The most obvious feature of a lateral flow test from the point of view of a user is the clarity and strength of the blue line or lines when the test is run.  These lines are formed by the collection of minute blue latex particles, carried along in the flow of liquid and then binding at specific points on the membrane.  Uniformity and consistency of line is achieved by very accurate dispensing of reagents through fine jets on the Biodot RR4500 spraying equipment.

Spraying of reagents is carried out at 45-50% relative humidity to ensure consistent droplet formation.  We spray 100m of membrane (sufficient for 18,000 tests) in a continuous process, on preset programmes to avoid handling the delicate membranes.  Machine vision systems constantly monitor the deposition of reagents to ensure spraying is within close tolerances.

After spraying reagents, the next step is to put together the various types of membrane into the composite strip which is then cut into 5mm widths and built into the plastic housing.  Combining up to five separate components into one composite strip is carried out on a Biodot Reel to Reel Laminator, producing 100m in one run.

Laminating and assembly of the lateral flow tests is carried out under strict environmental conditions of low relative humidity in order to ensure a long shelf life for the final product.  The 5mm-wide strips of composite membrane are placed into the familiar plastic housing in a fully automated assembly machine produced by Kinematic in the USA.  This state of the art equipment has over 50 sensors to monitor every stage of the process – from checking whether the membranes have been sprayed to the consistency of pressure applied to the two halves of the assembled test.

Investment in state of the art manufacturing equipment and facilities means the consistency and reliability of Pocket Diagnostic tests is guaranteed.  For high performance in the field, quality of manufacture really does matter, so perhaps next time you look at an LFD, you’ll regard it in a different light.