High bilirubin levels in newborns may be natural and temporary. However, high bilirubin in adults could be a sign of an underlying health condition, such as jaundice, gallstones, and liver issues.

Bilirubin is a yellowish substance in your blood. It forms after red blood cells break down and travel through your liver, gallbladder, and digestive tract before excretion.

The condition of having high bilirubin levels is called hyperbilirubinemia. It’s usually a sign of an underlying condition, so following up with a doctor is essential if test results show you have high bilirubin.

It’s also a common temporary condition in newborns.

Read on to learn more about the symptoms of high bilirubin and what can cause it.

Typically, adult bilirubin levels fall between 0.2 and 1.2 milligrams per deciliter (mg/dL). Anything above 1.2 mg/dL is usually considered elevated.

For children ages 15 days to 18 years, healthy bilirubin levels should be less than 1.0 mg/dL.

Understanding what constitutes an elevated value for newborns depends on what condition the doctor is treating. Doctors will usually worry if bilirubin rises a certain amount in 24 hours.

For example, a level of 8 mg/dl may not seem too concerning on day 2 of life, but if the day 1 value was 2 mg/dl, that 6 mg/dl rise can indicate a need for closer monitoring and treatment.

Having high bilirubin can be a sign of several conditions. Your doctor will take your symptoms, as well as any other test results, into account to help narrow down a diagnosis.

  • Gallstones: These develop when substances like cholesterol or bilirubin harden in your gallbladder. Your gallbladder stores bile, a digestive fluid that helps break down fats before they enter your intestines.
  • Gilbert’s syndrome: This is a genetic liver condition that causes your liver not to process bilirubin properly. This causes the bilirubin to build up in your bloodstream.
  • Liver dysfunction: This can be any condition that affects the function of your liver and causes bilirubin to build up in your blood. This is a result of your liver losing its ability to remove and process bilirubin from your bloodstream. Examples include cirrhosis, liver cancer, or autoimmune hepatitis.
  • Hepatitis: This happens when your liver becomes inflamed, often due to a viral infection. When it’s inflamed, your liver can’t easily process bilirubin, leading to a buildup of it in your blood.
  • Bile duct obstruction: Bile ducts connect your liver to your gallbladder and the opening of your small intestine, called the duodenum. They help to move bile, which contains bilirubin, from your liver and gallbladder into your intestines. Bile can’t be drained adequately if these ducts become inflamed or blocked. This can lead to an increased level of bilirubin.
  • Intrahepatic cholestasis of pregnancy: This is a temporary condition during the last trimester of pregnancy. It causes bile drainage from your liver to either slow down or stop entirely. This makes it harder for your liver to process bilirubin from your blood, leading to high bilirubin levels.
  • Hemolytic anemia: This happens when blood cells break down too quickly in your bloodstream. It’s sometimes passed down genetically, but autoimmune conditions, an enlarged spleen, or an infection can also cause it.

Bilirubin levels in newborns

Many babies have high bilirubin a few days after birth, causing newborn jaundice. This temporary condition usually resolves on its own within a few weeks.

It happens because newborns have more red blood cells and break them down more quickly, but their livers are not developed enough to keep up.

Before being born, the pregnant person’s liver helps with this task. A newborn’s liver is only about 1% as active as an adult’s.

In most cases, higher bilirubin levels will lead to jaundice between 1 and 3 days after birth. Bilirubin levels can peak as high as 18 mg/dL on the fourth or fifth day, and jaundice typically clears up within 2 weeks as the liver matures.

Feeding 8 to 12 times per day helps to promote regular bowel movements, which help to remove bilirubin from the body.

If jaundice occurs within the first 24 hours after birth, or if bilirubin levels are especially high or don’t begin to fall on their own, doctors may intervene with treatments such as:

If you have high bilirubin, your symptoms will depend on the underlying cause. You can have mildly high bilirubin and have no symptoms at all.

With moderately high bilirubin, you may only have jaundice, which is a yellowish color in your eyes and skin. Jaundice is the main sign of high bilirubin levels.

Other general signs of illnesses that cause high bilirubin can include:

Bilirubin levels are usually tested by taking a blood sample. A doctor will usually order this to check your liver function if you or your newborn are experiencing symptoms of high bilirubin or jaundice.

In newborns, blood is typically taken from the heel. In some cases, doctors might use blood from the umbilical cord.

For adults, blood is usually taken from one arm. You may need to fast before your blood test.

Two types of bilirubin will be measured: conjugated bilirubin and unconjugated bilirubin. The ratio between these two types of bilirubin will help narrow down the underlying cause of high bilirubin levels.

Sometimes, a urine sample will be used to test bilirubin levels. No bilirubin shouldn’t be present in urine, so any bilirubin found in a urine sample indicates an underlying condition.

Should I be worried about high bilirubin levels?

In many cases, high bilirubin isn’t a sign of anything that needs immediate treatment.

But if you notice any of the following symptoms, call a doctor or head to urgent care just in case:

  • intense abdominal pain or tenderness
  • drowsiness or disorientation
  • black or bloody stools
  • vomiting blood
  • a fever of 101°F (38.3°C) or higher
  • easy bruising or bleeding
  • red or purple skin rash

What does it mean when your bilirubin levels are high?

High bilirubin levels often mean that your liver isn’t filtering bilirubin the way it’s supposed to. There are many causes for this in adults. In newborns, the cause is usually newborn jaundice.

Does high bilirubin always mean liver damage?

High bilirubin levels may mean a problem with your liver, but not necessarily. There are causes unrelated to the liver that can raise your bilirubin levels, such as hemolytic anemia.

High bilirubin levels usually indicate that something is not working as expected in your liver or gallbladder. Some of these conditions aren’t too serious, but monitoring and treating them is essential.

Anyone with jaundice, the main sign of high bilirubin levels, should contact their doctor. If your doctor isn’t immediately sure what’s causing your high bilirubin levels, you may need to return for additional blood, liver function, or other tests.