Patient education: Newborn screening (The Basics)

What is newborn screening? — These are routine tests that check for health problems in newborn babies. "Routine" means that the screening tests are done on all babies, even if they appear healthy.

Why does my baby need screening tests? — Even if a baby seems healthy, it is still possible that they could have a health problem you cannot see. If there is a problem, screening lets the doctor find it early. This way, treatment can start right away.

How are newborn screening tests done? — They are done in different ways. They include:

●"Blood spot" screening panel – A few drops of blood are taken from your baby's heel. The blood is placed on a piece of filter paper, then sent to a lab for testing. "Panel" means that the blood is tested for many different things.

●Hearing screen – This can be done in 2 different ways. One test uses a small microphone and earphone placed in the ear. The other uses 3 small devices called "electrodes." These go on the forehead, back of the neck, and behind the ear. Both tests are painless and only take a few minutes. If your baby doesn't pass the first test, they might get a second test before going home.

●Pulse oximetry screening – This is a way to check for signs of a heart problem. A machine called a "pulse oximeter" checks the baby's oxygen level. If it is low, the baby might get other tests like a chest X-ray or an "echocardiogram." An echocardiogram uses sound waves to create a picture of the baby's heart.

●Bilirubin screening – Bilirubin is a substance in the blood. When a baby's bilirubin level is too high, it causes "jaundice." This is when the skin and whites of the eyes look yellow. Bilirubin screening can be done with a blood test or with a machine that measures bilirubin through the skin. Some hospitals do this screening in all newborns. Others do it only if the baby looks like it might have jaundice.

When is screening done? — Newborn screening tests are usually done before the baby goes home. For healthy babies, testing is usually done 1 to 2 days after birth:

●The blood spot test is usually done 24 to 48 hours after birth. If a baby is tested before 24 hours, they might need to be tested again. Some places use a "2-screen" process for all babies. This means that the baby is tested at 24 to 48 hours, and then tested again when they are 1 to 2 weeks old. The second test usually happens during a regular check-up.

●The hearing screen is done after the baby is 12 hours old and before going home.

●Pulse oximetry screening is done 24 to 48 hours after birth.

●Bilirubin screening is done 24 to 48 hours after birth. If a blood test is used, it is usually done at the same time as the blood spot test.

For babies who need intensive care in the "NICU," screening might be done at different times. Your doctor will talk to you about the right timing for your baby.

What health problems is my baby tested for? — Local public health agencies often decide which tests are routinely done. Different countries and regions have different guidelines.

In the US, the recommended newborn screening includes tests for many conditions. Examples include:

●Phenylketonuria – This is a condition where the body cannot break down a chemical called "phenylalanine." This chemical is harmful to brain development.

●Other metabolic disorders – The metabolic system controls certain chemicals in the body. These chemicals control how the body turns food into energy and gets rid of waste. With metabolic disorders, the body doesn't make an important chemical. This can cause developmental delays and other long-term health problems. There are many different metabolic disorders.

●Immunodeficiency disorders – These are conditions where the body's infection-fighting system, called the "immune system," doesn't work properly. Babies and children with these disorders get frequent and severe infections. Many newborn screening tests check for a serious form of this called "severe combined immunodeficiency."

●Cystic fibrosis − This is a disease that causes thick mucus and other fluids to build up and clog different parts of the body. It can affect the lungs, pancreas, liver, and intestines. People with cystic fibrosis have frequent lung infections and problems with digestion.

●Congenital hypothyroidism – This is a condition that causes a baby to have too little thyroid hormone. This can lead to problems with growth and development.

●Congenital adrenal hyperplasia – This is a genetic disorder that affects how the body responds to stress. In this condition, the adrenal glands do not make a normal amount of stress hormone (cortisol) and other hormones. There are different types of congenital adrenal hyperplasia. The most severe form can be life-threatening in newborns if not found early.

●Sickle cell disease and thalassemia – These are conditions that affect red blood cells. In sickle cell disease, the size and shape of the red blood cells are abnormal. It is a painful condition that causes many long-term health problems.

●Spinal muscular atrophy – This is a disorder that causes poor muscle tone and weakness. It affects muscles in the arms and legs. It also affects the muscles that control swallowing and breathing.

●Hearing loss – Hearing loss in newborns can happen for many different reasons. These include infections, genetic causes, and problems with how the ears developed before birth. Finding out about hearing loss early is important so the baby can get treatment. This will help with their language development and learning to talk.

●Congenital heart defects – These are heart problems that a baby can be born with. Some can lead to serious problems within the first few days or weeks of life if not treated.

●Hyperbilirubinemia or newborn jaundice – "Hyperbilirubinemia" means high levels of bilirubin in the blood. This causes jaundice, which is when a baby's skin or white part of the eye turns yellow. Very high levels of bilirubin can be harmful to the newborn’s brain.

Your baby might need additional tests if:

●There were health problems during pregnancy – Examples include certain infections or diabetes.

●The baby was born early ("preterm").

●An older sibling had a serious health problem, or there is a health problem that runs in the family.

●Your baby has an increased risk for a specific health problem – For example, babies who weigh much more or much less than normal are at risk for low blood sugar. In these cases, doctors usually do screening tests to check for this.

Will my baby need to be tested again? — Your baby might need to be tested again a few weeks after birth if:

●There is a problem with the first blood spot sample.

●Your baby does not pass the hearing screen before going home.

●Your baby is born early or weighs much less than normal.

●Your baby got a medicine, transfusion, or other treatment that might have affected the test.

●The results of the first test are abnormal.

●You are in an area that uses a 2-screen process for all babies.

When will I know the results? — If there are any concerns about the results of the hearing, pulse oximetry, or bilirubin screening, the doctors will talk with you before your baby goes home.

Results of the blood spot panel usually take a bit longer. In most cases, the results will be sent to your baby's regular doctor. If any are abnormal, the doctor or the newborn screening program will contact you. If you have any concerns about the tests, ask your baby's doctor during regular check-ups.

What else should I know?

●Most of these screening tests check for rare conditions. Most of the time, results are normal.

●A positive test result does not always mean that the baby has a health problem. When a screening test is positive, more tests are often needed. Sometimes, additional tests find that the baby actually does not have the condition. When this happens, the original test result is called a "false positive." For some screening tests, false-positive results are more common than true-positive results. But sometimes, a false-positive result can help the doctor find another problem.

●If you are told that your baby needs additional testing, follow all instructions for when and where to go.

When should I call the doctor? — Some conditions that newborns are screened for can cause serious health problems during the first few weeks after birth. Call the doctor right away if your baby:

●Is not eating normally

●Is unusually sleepy or hard to wake

●Has severe or worsening jaundice

●Seems to be working harder than normal to breathe

●Turns blue in the face, skin, lips, fingernails, or toenails

●Has a fever of 100.4°F (38°C) or higher

●Does not have a wet diaper for 8 hours or longer

●Spits up a lot

●Has blood in their diaper

●Cries for longer than 2 hours without stopping

More on this topic

Patient education: Screening for hearing loss in newborns (The Basics)
Patient education: What to expect in the NICU (The Basics)
Patient education: Caring for your newborn (The Basics)
Patient education: When a baby is born premature (The Basics)
Patient education: Jaundice in babies (The Basics)

Patient education: Jaundice in newborn infants (Beyond the Basics)