Searched and did not find an answer to my question. As the title suggests, I installed an Amsoil BMK21 bypass with the BP90 filter on my 2007 Honda Civic Si at 93k miles. The car is driven hard/raced, and I have many years of UOAs taken pre-bypass showing great results (thread: http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3875263/'07_Civic_Si_Amsoil_ss_0w30_8k#Post3875263). The next UOA will be the first one post-bypass install. The bypass was installed during an oil change with 6 fresh quarts of Amsoil AZO 0w30 on 9/11/15. I currently only have 7000 miles on this oil fill with one full quart of makeup oil added. I plan to get it analyzed soon. My question is in regard to the way the bypass setup could skew UOA results. Since none of my previous UOA's included using a bypass setup, future results seem less comparable to old results. The way I think of it, the bypass filter is 98.7% efficient at two microns. The full flow Amsoil Ea15k13 filter is 98.7% efficient at 20 microns. Won't filtering particles with the same percent efficiency at 18 less microns also filter wear metals in the 3-19 micron range that oil analysis would usually register (assuming Blackstone Lab's equipment registers particles of this size)? Is this thought process on the right track? Could I use an extraction pump to analyze this oil (without changing it) to keep an eye on it? Should I sample as usual when I change the oil? Or do I need to cut the bypass filter open and send a sample of the pre-bypass filter media oil to Blackstone?