Do you mean some lateral story drift imposed by the gravity loading? I would think you just combine this load case with the RSA load case results.
The load combinations including vertical loading and seismic loading would be such that the drift includes both. The caveat is that you only need to amplify the seismic drift. But certainly at the end you want your static drift + seismic drift to be within the limits in ASCE 7-16 or other reference document.
It's not clear what you're asking. There is the static analysis from applying a "equivalent lateral force" method of seismic analysis. I do like to consider this personally. It helps me to give the RSA results a "reality check". If the lateral drift I'm getting from the two methods is very different, then I generally want to understand why.
