I have been working mostly on half strip LFIA where i mix antigen target and conjugate solution and test on half strip.

When i change to full strip, there are some problems;

1. The control line is fine but the test line does not appear or sometimes appear very faint after more than 30 minutes.

2. The conjugate solution turns to purple when dried. It still flows when rewetted but the ability to flow seems to degrade quickly.

I pretreated the conjugate pad (glass fiber gf33) with mixture of borate buffer, BSA 1%, PVP-40 and triton x-100 solution before depositing conjugate solution.

Does anyone have any idea or suggestion on how to make the test line visible on full strip?