Netherlands Forensic Institute spokeswoman Inge Oevering says experts are first establishing whether the bone is human before comparing its DNA to that of Holloway.
Holloway, then 18, disappeared in 2005 while on a high school graduation trip to the Caribbean island of Aruba.
Dutchman Joran van der Sloot, who faces separate murder charges in Peru, is suspected in Holloway's disappearance.
Dutch daily De Telegraaf reported Tuesday the bone was found by tourists on a beach Friday.
Oevering says prosecutors in Aruba will announce the results. She could not say how long the tests would take.