Description: Bilirubin Fractionated is a blood test that is used to screen for or monitor liver disorders, hemolytic anemia, and neonatal jaundice.
Also Known As: Total Bilirubin Test, TBIL Test, Neonatal Bilirubin Test, Direct Bilirubin Test, Conjugated Bilirubin Test, Indirect Bilirubin Test, Unconjugated Bilirubin Test
Collection Method: Blood Draw
Specimen Type: Serum
Test Preparation: No preparation required
When is a Bilirubin, Fractionated test ordered?
When someone shows evidence of abnormal liver function, a doctor will usually request a bilirubin test along with other laboratory tests. A bilirubin test may be ordered when a patient:
- Evidence of jaundice is visible.
- Has a history of excessive alcohol consumption
- Has a possible drug toxicity
- Has been exposed to viruses that cause hepatitis
Other signs and symptoms to look out for include:
- Urine with a dark amber tint.
- Swelling and/or pain in the abdomen
- Fatigue and malaise which are common symptoms of chronic liver disease.
In babies with jaundice, measuring and monitoring bilirubin is considered routine medical therapy.
When someone is suspected of hemolytic anemia as a cause of anemia, bilirubin tests may be ordered. In this instance, it's frequently ordered in conjunction with other hemolysis-related tests such a complete blood count, reticulocyte count, haptoglobin, and LDH.
What does a Bilirubin, Fractionated blood test check for?
Bilirubin is an orange-yellow pigment that is largely formed as a byproduct of heme degradation. Heme is a component of hemoglobin, a red blood cell protein. Bilirubin is eventually digested by the liver, which allows it to be excreted from the body. This test assesses a person's liver function or aids in the diagnosis of anemias caused by RBC destruction by measuring the quantity of bilirubin in their blood.
After roughly 120 days in circulation, RBCs generally disintegrate. Heme is transformed to bilirubin as it is released from hemoglobin. Unconjugated bilirubin is another name for this type of bilirubin. Proteins transport unconjugated bilirubin to the liver, where sugars are linked to bilirubin to produce conjugated bilirubin. Conjugated bilirubin enters the bile and travels from the liver to the small intestines, where bacteria break it down further before it is excreted in the stool. As a result, bilirubin breakdown products give stool its distinctive brown hue.
A normal, healthy human produces a tiny quantity of bilirubin each day. The majority of bilirubin comes from damaged or degraded RBCs, with the rest coming from bone marrow or the liver. Small amounts of unconjugated bilirubin are normally discharged into the bloodstream, but there is almost no conjugated bilirubin. Laboratory tests can measure or estimate both types, and a total bilirubin result can be presented as well.
A person may appear jaundiced, with yellowing of the skin and/or whites of the eyes, if the bilirubin level in their blood rises. The pattern of bilirubin test results can provide information to the health care provider about the ailment that may be present. When there is an exceptional quantity of RBC destruction or when the liver is unable to handle bilirubin, unconjugated bilirubin levels may rise. Conversely, conjugated bilirubin levels can rise when the liver can process bilirubin but not transmit the conjugated bilirubin to the bile for elimination; this is most commonly caused by acute hepatitis or bile duct blockage.
In the first few days after birth, increased total and unconjugated bilirubin levels are fairly common in infants. This condition is known as "physiologic jaundice of the newborn," and it develops when the liver of a newborn is not yet mature enough to handle bilirubin. Physiologic jaundice in newborns usually goes away after a few days. RBCs may be damaged in newborn hemolytic illness due to blood incompatibility between the infant and the mother; in these circumstances, treatment may be necessary since large amounts of unconjugated bilirubin might harm the newborn's brain.
Increased total and conjugated bilirubin levels in infants can be caused by biliary atresia, an uncommon but life-threatening congenital disease. To avoid catastrophic liver damage that may necessitate liver transplantation during the first few years of life, this problem must be rapidly recognized and treated, usually with surgery. Despite early surgical therapy, some children may require liver transplants.
Lab tests often ordered with a Bilirubin, Fractionated test:
- Hepatitis A
- Hepatitis B
- Hepatitis C
- Complete Blood Count (CBC)
- Reticulocyte Count
Conditions where a Bilirubin, Fractionated test is recommended:
- Liver Disease
- Hemolytic Anemia
Commonly Asked Questions:
How does my health care provider use a Bilirubin, Fractionated test?
A bilirubin test is used to detect an abnormally high quantity of the substance in the blood. It can be used to figure out what's causing your jaundice and/or diagnose illnesses like liver disease, hemolytic anemia, and bile duct blockage.
Bilirubin is an orange-yellow pigment that is largely formed as a byproduct of heme degradation. Heme is a component of hemoglobin, a red blood cell protein. Bilirubin is eventually digested by the liver, which allows it to be excreted from the body. An increased blood level can be caused by any disorder that speeds up the breakdown of RBCs or impairs the processing and elimination of bilirubin.
Laboratory testing can measure or estimate two types of bilirubin:
Unconjugated bilirubin—unconjugated bilirubin is formed when heme is released from hemoglobin. Proteins transport it to the liver. Small levels of the substance may be found in the blood.
Sugars are attached to bilirubin in the liver, resulting in conjugated bilirubin. It enters the bile and travels from the liver to the small intestines before being excreted in the feces. In normal circumstances, there is no conjugated bilirubin in the blood.
A chemical test is usually done to determine the total bilirubin level first. If the total bilirubin level rises, a second chemical test can be used to detect water-soluble forms of bilirubin, known as "direct" bilirubin. The amount of conjugated bilirubin present can be estimated using the direct bilirubin test. The "indirect" amount of unconjugated bilirubin can be estimated by subtracting the direct bilirubin level from the total bilirubin level. The pattern of bilirubin test results can provide information to the healthcare professional about the ailment that may be present.
Bilirubin is measured in adults and older children to:
- Diagnose and/or monitor liver and bile duct disorders.
- Evaluate patients with hemolytic anemia
- Distinguish between the causes of jaundice in babies.
Only unconjugated bilirubin is raised in both physiologic jaundice and hemolytic illness of the infant.
Damage to the newborn's liver from neonatal hepatitis and biliary atresia will also raise conjugated bilirubin concentrations, which is generally the first indication that one of these less common disorders is present.
Because excessive unconjugated bilirubin harms growing brain cells, it is critical to detect and treat an increased amount of bilirubin in a newborn. Mental retardation, learning and developmental impairments, hearing loss, eye movement disorders, and mortality are all possible outcomes of this damage.
What do my bilirubin test results mean?
In adults and children, increased total bilirubin, primarily unconjugated bilirubin, could be caused by:
- Hemolytic or pernicious anemia are two types of anemia.
- Reaction to a transfusion
- Gilbert syndrome
When conjugated bilirubin levels are higher than unconjugated bilirubin levels, there is usually a problem with bilirubin removal by the liver cells. This can be caused by a variety of factors, including:
- Hepatitis caused by a virus
- Reactions to drugs
- Alcoholic hepatitis
When the bile ducts are blocked, conjugated bilirubin is raised more than unconjugated bilirubin. This can happen, for example, when:
- In the bile ducts, there are gallstones.
- Damaging of the bile ducts due to tumors
Increased bilirubin levels can also be caused by rare hereditary illnesses that involve aberrant bilirubin metabolism, such as Rotor, Dubin-Johnson, and Crigler-Najjar syndromes.
Low bilirubin levels are usually not a cause for worry and are not monitored.
A newborn's high bilirubin level may be transient and diminish within a few days to two weeks. However, if the bilirubin level exceeds a crucial threshold or rises rapidly, the cause must be investigated so that appropriate treatment can be started. Increased bilirubin levels can be caused by the rapid breakdown of red blood cells as a result of:
- Incompatibility of the mother's blood type with that of her child
- Infections that are present at birth
- oxygen deficiency
- Liver disease
Only unconjugated bilirubin is elevated in most of these disorders. In the rare disorders of biliary atresia and newborn hepatitis, increased conjugated bilirubin is found. To avoid liver damage, biliary atresia necessitates surgical surgery.
We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.