When I spray Abs on the nitrocellulose membrane for my lateral low assay for both control and test lines, the test results show that the control line intensity is so weak. However, when I spray control line Ab alone, the intensity of that control line when testing with blank is decent.

I use goat anti-mouse for control line, mouse anti-PAMG-1 as a test line, and gold conjugate is another mouse anti-PAMG-1. Other parameters are covered, i.e. membrane type, conjugate, running buffer, Ab diluent, etc. but nothing comes up suspeciously.

Two hypotheses; one is the test line Ab competes with gold conjugate Ab to bind at the control line, another is the humidity that might play a role in binding capacity of those Abs on the nitrocellulose membrane. At this time of the year, the %RH is very low. I have read that during spraying Abs, the optimal %RH should be up to 50%.

Let me know your thoughts.

Thanks!

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