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Good question, this is a process that should always be considered as there are so many different types of proteins out there and the same membrane, MWCO, device, etc is not always best for each. The following steps should be taken in considering how best to improve concentrations and recoveries; 1) consider the sample and molecule properties, changes to pH can increase conformational rearrangements, lower temperatures can reduce concentration rates, etc. 2) Pick the right membrane, UF is known for not having many membrane options, but you should at least test whether regenerated cellulose (RC) or Polyethersulfone (PES) is best for your protein and use the right membrane for each protein. 3) Select the right MWCO and device, typically a MWCO 1/3 the size of the target is suitable and a device that is right for the total sample volume. 4) Use appropriate device treatment methods, such as pre-rinsing to remove analytes or flushing with a non-interfering protein to passivate the binding sites and reduce loss. Finally, 5) Consider sample control methods, such as using dead stops within devices to pipette out all the retentate or pre-filling the filtrate tube to control the final volume of the retentate.