Cognomen เลิศเกษม (เลิศเกษม 
, Lerkkasem , Lertkasem 
) , in all the world, is a rare family name. The cognomen เลิศเกษม is habitual in Thailand, where it is a rare surname, and the United States, where it is an extremely rare surname.
| VARIANT | COUNTRY |
|---|---|
| Lerdkasem, Lerkkasem, เลิศเกษม | Thailand |
| Lertkasem | Thailand, United States |