The reference range for direct bilirubin is 0 to 6.8 μmol/L, so there is no possibility that direct bilirubin is low, and the direct bilirubin result alone cannot determine if there is a liver problem. Direct bilirubin is produced by combining indirect bilirubin with glucuronic acid in the liver, also known as conjugated bilirubin. Direct bilirubin is soluble in water, so it can be excreted in the urine. The reference range for direct bilirubin is 0 to 6.8 μmol/L, so there is no possibility for direct bilirubin to be low, so it is not possible to tell if there is liver disease from a direct bilirubin result. If liver disease is suspected, further tests such as liver and gallbladder ultrasound are needed to find the cause. It is also necessary to eat a light diet, take less greasy, fried, barbecue and other foods, avoid smoking and alcohol, but also to ensure enough sleep and keep emotional well-being.