Bilirubin is normally high in thals due to the high turnover of red blood cells. This can fluctuate depending on the turnover rate. And much is unknown about what may cause hemolysis in thal patients. We know that eating broad beans, like fava beans, or being exposed to various chemical fumes and drugs can cause hemolysis in alpha thals, and here at thalpal, we have heard from beta minors who have had instances of hemolysis set off by exposure to fumes, and even some common household scents like artificial perfumes and colognes and scented laundry products. If this does happen, you will notice a lack of energy, as it causes a brief anemia. Should this be a possibility, observe what exposures you've had leading up to the sudden drop in Hb. It may be that you had some exposure to fumes at the time. Certain drugs like sulfa antibiotics, can also cause red cell destruction and a sudden drop in Hb. It is worth watching the level to see if you can match the increases to any specific food you've eaten or chemical you've been exposed to. I have heard of everything from being exposed to cigarette smoke to the scent of dryer fabric softener sheets setting off hemolysis.
However, bilirubin can be affected by other things, as well. While looking for an answer for another member, I learned that drinking wine raises the bilirubin level, which explained his rise, as he had wine over the holidays. A note about that is that it is not believed to be harmful when caused by wine, as it is accompanied by a rise in antioxidant levels. Diet can also be a factor, and I suspect in the other case, that overindulging in holiday food may have contributed to the higher bilirubin.
While the higher bilirubin doesn't normally cause a problem, when it is high constantly it can lead to the formation of gallstones or more likely, sludge in the gallbladder. Many minors eventually have their gallbladders removed due to ducts being blocked by sludge.