Collection of sample This test is performed with the patient's serum. There is no restriction for a fasting sample. The test can be done by a random blood sample the patient. About 3 to 5 ml of blood is collected in a plain test tube, and blood is allowed to clot to get clear serum. In infants, the sample may be collected from the heel. The blood sample is centrifuged for 5 to 10 minutes and the serum is separated for the test. The patient's serum is stable at 4° C for 3 days and protects it from the light. Note: Bilirubin is photo-sensitive (photo-oxidized) so keep the sample in dark place otherwise false-negative results may obtain. Precautions Avoid sample from hemolysis Do not expose the sample to light. Exposure of sample to light may decrease the value. If there is a delay in performing the test then keep the sample in dark and refrigerate it. Avoid shaking of the test tube as it may lead to an inaccurate result. Pathophysiology Serum bilirubin is a very useful test to evaluate liver functions. Raised level of bilirubin can be seen in the hepatic and post-hepatic type of jaundice. Clinically jaundice appears when the level of bilirubin is more than 2 mg/dl. Direct (or conjugated) bilirubin: It is water-soluble and dissolves in water and is synthesized in the liver form indirect bilirubin. Read Also Article continued below Bilirubin: Total, Direct and Indirect Bilirubin (Different Types of Jaundice) This test is performed for the diagnosis and differentiation of jaundice. This test is also done in a patient with hemolytic anemia in adult and newborn. Read more... Normal Values Total bilirubin 0.3 to1.0 mg/dL or 5.1 to 17.0 mmol/L Direct bilirubin 0.1 to 0.3 mg/dL or 1.0 to 5.1 mmol/L Indirect bilirubin 0.2–0.7 mg/dL Raised level of direct bilirubin is seen in Gallbladder tumors Gallstones Dubin-Johnson syndrome Rotor syndrome Obstruction of extrahepatic ducts or inflammatory scarring Can be resolved by the surgery Drugs may cause cholestasis