Sept 17 my sons bilirubin was elevated at 1.9 oct 17 abdominal sonogram: normal w/no cholelithiasis, bile duct dilatation then, two normal results, dec 17 and apr 18 now its high again at 2.6 can skipping meals/poor diet cause fluctuations?

Wouldn't think so: He may have a peculiar problem called a bilirubin transport disorder. The Dubin- Johnson syndrome is a rare but benign disorder of bilirubin transport that is caused when you inherit the recessive gene from both parents. It leads to unexplained bilirubin elevations in otherwise healthy people. Other issues would need to be explored but this is a possibility.