What Are Bilirubin Levels?

Bilirubin is a waste product that is processed by the liver and is responsible for giving bile, which helps your body digest fats, its yellow color. While low bilirubin levels are typically not a cause for concern, elevated or high bilirubin (hyperbilirubinemia) can cause jaundice, a condition in which your skin or the whites of your eyes turn yellow.

In adults, high levels may indicate a benign genetic disorder, such as Gilbert syndrome, or an underlying issue with your liver. Elevated bilirubin in infants is quite common and may be caused by dehydration or preterm birth. High bilirubin levels are often treatable in adults and infants.

Your bilirubin level can indicate how well your liver and other bodily processes are functioning.

Your body produces bilirubin in two ways. About 80 percent of the bilirubin in your body is a byproduct of a natural process in which red blood cells die, break down, and are processed by the organs, mostly the spleen and liver. Smaller amounts of bilirubin come from proteins found in other tissues, mainly bone marrow, the liver, and muscles.

In adults, normal total bilirubin levels in the blood are typically less than 1 milligram per deciliter (mg/dL).

Jaundice may present when your bilirubin levels reach about 3 mg/dL, but you can start seeing changes in the color of the whites of your eyes when levels reach about 2 mg/dL, says Karl Kwok, MD, a gastroenterologist with Kaiser Permanente Southern California in Los Angeles. Elevated bilirubin levels, ranging from 1 to 4 mg/dL, typically don't require treatment.

“The story we hear, not uncommonly, is that someone has a big event coming up like a final exam or a big work presentation, and they notice the whites of their eyes appear a bit yellow,” says Dr. Kwok, which prompts testing, a diagnosis, and treatment.

In adults, very high levels start around 4 mg/dL which is when doctors typically start intervening, Kwok says. At this level, you may experience even more noticeable skin discoloration, as well as itching and fatigue.

Elevated bilirubin levels are much more common in newborns than in adults, especially those born prematurely. In newborns, normal bilirubin levels typically range between 1 and 12 mg/dL.

However, the threshold for what is normal varies by the hour and day of life, gestational age, and what risk factors are present, says Katherine Guttman, MD, neonatologist at the Mount Sinai Kravis Children's Hospital in New York City. While elevated levels often resolve on their own, doctors will typically begin treatment when a newborn's bilirubin levels reach 15 mg/dL in the first 48 hours or 20 mg/dL in the first 72 hours.

Although it's possible to have low bilirubin levels, this generally isn't something to worry about. Low levels can be a side effect of taking antibiotics, birth control pills, sleeping pills, or seizure medications, and they can resolve on their own.

The key indicator of elevated bilirubin in adults and infants is jaundice, which usually affects the whites of the eyes first. “The whites of the eyes or skin can turn temporarily yellow. That, in essence, is a check engine light. It alerts the person that hey, perhaps I should look into this,” says Kwok.

However, people with a benign genetic condition, such as Gilbert syndrome, may not experience symptoms when their bilirubin levels are mildly elevated.

Symptoms of High Bilirubin in Adults

Common symptoms of high bilirubin in adults can include:

Jaundice
Frequently itchy skin
Dark-colored urine or light-colored stool
Bloating
Pain in the abdomen
Swelling in the ankles and legs
Nausea and vomiting
Lack of appetite
Fatigue
Weakness

Symptoms of High Bilirubin in Infants

Symptoms of high bilirubin in infants can differ from those in adults. Common signs and symptoms can include:

Jaundice
Not feeding well
Being sleepier than normal
Dark yellow urine (it should be colorless)
Have pale stool (it should be yellow or orange)
Dehydration

In addition, infants may experience dehydration, Guttman says. This can cause infants to urinate less.

High levels occur when your body isn't able to get rid of bilirubin and it builds up in the blood. The causes are notably different for adults and infants.

High Bilirubin in Adults

In adults, high bilirubin levels could be a side effect of a new medication, such as antibiotics like rifampin (Rifadin) or probenecid, a medication used to reduce uric acid buildup.

In addition, it could be a result of herbal products, such as kava and green tea extracts, or heavy alcohol use. If you begin to notice symptoms, it's important to talk with your doctor to determine the underlying cause. High bilirubin may resolve on its own, or it may require taking a different medication or making certain lifestyle changes.

In other cases, it may be a sign of an underlying medication condition, such as:

Liver diseases, such as hepatitis and cirrhosis
Hemolytic anemia, when blood cells are destroyed prematurely
Bile duct obstructions, usually from a gallstone, but sometimes from a tumor

High bilirubin levels may also be the result of certain genetic disorders, including:

Gilbert Syndrome This is a common condition where the liver doesn't process bilirubin as it should. It's harmless and doesn't require treatment.
Dubin‐Johnson Syndrome This is a rare and benign lifelong condition that doesn't require treatment. Bilirubin collects in the liver and bloodstream rather than moving out of the digestive system. It causes the liver to turn black.
Crigler-Najjar Syndrome This is a very rare congenital condition, occurring in 0.6 to 1 in 1 million newborns in the world. If not treated, it can lead to significant brain damage.

High Bilirubin in Infants

It isn't uncommon or much cause for worry if a newborn baby has elevated bilirubin levels within the first two to three weeks of life, says Dr. Guttman. In fact, about 60 percent of full-term infants and 80 percent of premature infants develop jaundice in the first week after birth.

Newborns have increased production of bilirubin because their hemoglobin, a protein found in red blood cells, turns over more quickly. At the same time, they're not able to clear bilirubin as well as adults. Newborns also take in more bilirubin from the intestine and pull it back into circulation.

Within those first couple of weeks, high bilirubin, which causes jaundice, is very treatable and likely not a sign of a long-term problem. In these cases, it may be caused by dehydration or breast milk jaundice.

“Once we get beyond those first few weeks, if you still have elevated bilirubin, it's usually indicative of a problem with the baby's liver,” Guttman says. Other causes of high bilirubin levels that persist in infants include:

A biliary flow obstruction, such as a cyst
Genetic causes, such as Dubin-Johnson syndrome
Down syndrome
Infections such as syphilis, HIV, or herpes

If you're experiencing symptoms and a doctor suspects that you may have elevated or high bilirubin levels, they may conduct a blood or urine test.

“Routine lab testing can usually get to the heart of the matter pretty quickly,” says Kwok. “Very high bilirubin levels can affect the nervous system in adults. The primary goal there is to see what is going on in the liver so we can prevent ongoing health issues.”

Bilirubin Blood Test

A blood test is most commonly used to detect elevated or high bilirubin. This test can be done in both adults and infants to measure the specific amount of bilirubin circulating in the blood.

In newborns, a doctor will prick the bottom of the foot to draw blood.

However, in adults, the sample is typically taken from a vein in the arm using a small needle. That sample will then undergo laboratory analysis to determine whether bilirubin levels are high.

Before taking a blood test, you may need to fast or stop taking certain medications for accurate results. If your blood test shows elevated or high bilirubin levels, your doctor will likely order additional tests, such as a liver panel, biopsy, urine test, or ultrasound, to determine the underlying cause.

Bilirubin Urine Test

A bilirubin urine test is typically part of a broader urinalysis that checks the overall health of your urinary tract and is done using a simple urine sample. Usually, there isn't any bilirubin in urine.

If your urine tests positive for bilirubin, your doctor may order further testing, such as a liver panel, to diagnose the underlying cause.

If your doctor is concerned about your high bilirubin levels, they may order a liver panel. Seeing a breakdown of conjugated and unconjugated bilirubin levels on this panel can help doctors narrow down the potential underlying cause, Kwok says.

High levels of conjugated bilirubin, or direct bilirubin, occur when the flow of bilirubin through the gastrointestinal system becomes sluggish. This may be caused by injury to liver cells, a blockage in the bile duct system, or a tumor, says Kwok.

High levels of unconjugated bilirubin, or indirect bilirubin, are caused by an overproduction of bilirubin. They may also be a result of an infection or a genetic condition, such as Gilbert syndrome, both of which cause greater turnover of red blood cells.

The best treatment for high bilirubin depends on the underlying cause.

Treating High Bilirubin in Adults

Moderately high bilirubin levels, such as those below 4 mg/dL, don't typically require treatment. Doctors will typically begin intervening when your levels are at or above 4 mg/dL. At this point, addressing underlying conditions, such as liver disease, can typically treat the root cause of high bilirubin.

If medications like rifampin (Rifadin) or probenecid are the cause, speak with your doctor about the possibility of switching to another drug.

If high bilirubin is caused by an obstruction, such as gallstones, you may require an endoscopic procedure or surgery to prevent repeat bouts of elevated bilirubin or to lower already elevated levels.

Gilbert syndrome does not require treatment and isn't considered dangerous. However, people with this condition can expect to have periodic bouts of high bilirubin, especially in times of physiologic stress, such as when fasting or exercising.

Treating High Bilirubin in Infants

High bilirubin is typically treated in infants using phototherapy. During the treatment, a healthcare provider will place the infant under a blue light to help flush bilirubin from their system. This treatment isn't harmful to the infant and takes place over one to two days.

Keeping the infant hydrated, particularly if elevated bilirubin is caused by dehydration, can help treat high bilirubin. This can involve supplementing breast milk with bottle feeding or administering intravenous fluids. “Depending on where you are in the country, that can even be done at home, but in some places, that needs to happen in the hospital,” Guttman says. “Those are our first line interventions and for the vast majority of infants, that is enough.”

For infants with a high risk of hemolytic anemia, in which red blood cells are destroyed, doctors may use a therapy called intravenous immunoglobulin (IVIG). This involves giving the infant human antibodies from blood donations through an IV.

“IVIG can be helpful because it helps address the immunologic issue that is causing them to break down the red blood cells; that's a limited number of patients, but it can be helpful for some babies,” Guttman says.

In extreme cases, in which levels are getting very high or the first lines of treatment are not working, a baby may need an exchange transfusion. This involves removing the baby's blood and replacing it with a donor's blood. “Most of the time we are able to manage with more conservative measures,” Guttman says.

High bilirubin levels do not cause long-term issues in the vast majority of infants. However, untreated severely high bilirubin levels can cause brain damage, hearing loss, and cerebral palsy. “It is exceedingly rare these days that it hits these levels because this is a very well-understood phenomenon,” Guttman says. “We are, at all costs, avoiding the levels getting to the point where it would cause that.”

It's not always possible to prevent high bilirubin in infants or adults, but there are a few ways to lower the risk.

How to Prevent High Bilirubin in Adults

In general, people can prevent high bilirubin levels by addressing its underlying causes, such as obstructions or liver disease.

In addition, eating a healthy diet full of whole grains, fruits, and vegetables, and getting regular exercise is associated with decreased risk of gallstones, which are a common cause of elevated bilirubin.

In people who have Gilbert syndrome, excessive stress and dehydration can trigger high bilirubin, says Kwok. Managing stress may help keep bilirubin levels down.

How to Prevent High Bilirubin in Infants

High bilirubin is very common in infants and not often preventable, Guttman says.

Mothers should be tested for Rh (Rhesus) factor negative blood type, which can be treated to avoid severe jaundice in newborns.

A doctor will typically recommend doing an Rh factor screening test during the first prenatal appointment.

Preventing dehydration can decrease an infant's risk of high bilirubin, too. Keep an eye on how often your infant urinates. In the first 24 hours, a diaper may only be wet two or three times. After that, a newborn baby's diaper should be wet almost every time you check it, Guttman says.

"Once a baby comes home, you certainly want to make sure they are urinating regularly," she says. "Talk to your pediatrician if you are concerned your baby isn't getting enough. You can supplement even temporarily with formula or meet with a lactation consultant to try to remedy dehydration."

Bilirubin is a waste product that is processed by the liver and gives bile its yellow hue. While low bilirubin levels aren't a cause for concern, high levels can lead to jaundice.
High bilirubin levels are common in infants. They're usually not a cause for concern as long as they're evaluated by a doctor.
In adults, high bilirubin levels are less common and could be due to any number of conditions. These include benign ones that require no treatment, such as Gilbert syndrome, and other more serious medical conditions, such as liver disease or bile duct obstruction.
High bilirubin levels are often very treatable in both infants and adults, though in some cases, they can be a sign of a more serious underlying condition.

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