What is the reason for the dark yellow complexion and liver function tests?

Patient's question:

Child not eating well, face yellow, did liver function tests, doctor said if hepatitis B surface antibody is positive

Doctor's answer:

It is recommended to check for possible zinc deficiency and digestive issues. Consider taking oral zinc gluconate and Shan Mai Jian Pi oral liquid to try. Avoid MSG and chicken essence, as they can easily lead to zinc deficiency and potentially cause low appetite. Additionally, be sure to control snack intake. Also, the weather being hot could be a factor or cause. Zinc deficiency can also lead to weakened immunity.