Jaundice question for 12 year old?

my girlfriends sister is 12 years old. shes a bit overweight but not as much. her sister noticed her eyes color changed a yellowish but she is not feeling sick. they doctor did some blood work and she got some kind of liver testing and what not. they will get the test tomorrow. can anyone tell me what can it be. please dont say liver failure. i want to merry her older sister but it will be difficult after something so horrible happens.