Cognomen ถ่องแท้ (Somchintana 
, Thongthae 
, ถ่องแท้) , across the world, is a rare family name. The family name ถ่องแท้ is characteristic of Thailand, where it is a rare surname, and the United Kingdom, where it is an extremely rare surname. Very seldom, ถ่องแท้ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Somchintana | Thailand, United States |
| Thongthae | United Kingdom, Thailand |