If you use alamode, find the environmental addenda, and use that.
For HUD direct, they have a convenient process where they test potential flaking paints for certain age of homes, if flaking is present. Handling much of it via property preservation. So sometimes I get corrected for calling the paint, because they have specific engagement that states within certain age ranges they run tests, and so appraisers don't need to call it.
But for typical mortgage lending, you don't have a client assisting you with lead testing, so there is no stop gap like that.
You see potentially lead based paint flaking off substantially for an older home, you photograph it closely and call repair.
http://www.HUD.gov/offices/lead/training/LBPguide.pdf Picked this up from another poster, good link to keep.
Your specific guidance is in there somewhere. http://portal.HUD.gov/hudportal/HUD?src=/program_offices/administration/hudclips/letters/mortgagee
This is the convenient one which filters out for appraisers: http://portal.HUD.gov/hudportal/HUD?src=/program_offices/housing/sfh/appr/apprmls
Bookmark, read up, and you'll have a great gameplan I'm sure.