I am trying to recreate a protocol to detect alpha-Gal on decellularized ECM.

The protocol I have been following has been heavily based on this patent : EP 2 626 701 A1 and utilizes the Thermo Fisher Polysorp plates (https://www.thermofisher.com/order/catalog/product/475094).

I am getting substantial binding across my entire plate regardless of the standard or sample loaded. There is nearly equivalent absorbance signal across all of my standard curve points, my samples and the spike-in/dilution controls and even across the wells with no coating and only HSA blocking. I believe this is indicating that the plastic surface itself is somehow binding the antibody (M86). Going through my notes I used 1% HSA/PBS blocking solution and the original protocol uses 1.5% so I can address that but otherwise I'm stumped on what other steps to even attempt next. Looking at the other surface treatment options they only seem even more likely to interact with the antibody?