I have itching all over the body. i have 1.6 mg/dl bilirubin level. gone through ultrasound, everything is normal. no gallstone. no yellowing of skin.

Likely unrelated: Your isolated bilirubin of 1.6 may be a normal finding for you (assuming all other liver tests are alright). Hepatitis testing done? Some people can have a slight elevation of bilirubin ; be normal for them, called gilbert's syndrome. The itching may be evaluated by a dermatologist for a skin condition.

Other causes: Of itching include most commonly skin infections or irritations. But rarely it can be caused by mononucleosis, or even lymphoma. Consult your doctor to investigate these other causes.