Last name ประเสริฐล้ำ (Prasertlum 
, ประเสริฐล้ำ) , worldwide, is a very rare cognomen. The last name ประเสริฐล้ำ is habitual in Thailand, where it is a very rare surname, and the United States, where it is an extremely rare surname. Much less frequently, ประเสริฐล้ำ is the forename as well as the last name.