Newborn screening tests explained

screening tests

Screening tests. All states require newborn screening tests for rare but serious conditions, including hearing loss, congenital heart defects, and metabolic disorders. These tests detect disorders that can cause long-term health problems, or even be fatal, if not diagnosed and treated promptly. Find out which screening tests your baby will have and what’s involved.

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What is a newborn screening test?

Newborn screening tests check for rare but serious conditions in babies just after birth. Tests are usually performed between 24 and 48 hours after your baby is born. The screening tests involve little to no discomfort for your baby.

All states require screening tests on newborns for at least 29 of 35 disorders, even if babies appear healthy. You can ask your baby’s doctor or check with your state’s newborn screening program for details on tests required in your state.

Most of the disorders the tests look for show no visible signs at birth. Catching them early can help doctors treat conditions before they cause lasting harm. The vast majority of babies don’t have the conditions they’re tested for, but about 5,000 babies in the U.S. are diagnosed with a newborn screening condition each year.

Keep in mind that screening tests only give preliminary information. Doctors use the tests to decide whether more precise diagnostic testing is needed to determine if there’s truly a problem.

Newborn screening tests

There are three main categories of newborn screening tests:

Newborn hearing test

There are two types of tests, and your baby’s hearing will be screened using one or both:

  • Otoacoustic emissions (OAE). This involves placing a soft earphone and microphone in your baby’s ear. The earphone plays sounds, and the microphone measures the ear’s response.
  • Auditory brain stem response (ABR). For this screening, soft earphones placed in the ears play sounds, and three electrodes on your baby’s head measure how her auditory nerve and brain stem respond.

With both screening tests, the process is painless, takes 5 to 10 minutes, and can be performed while your baby is asleep. If your baby doesn’t pass the hearing test, you’ll be referred to a pediatric audiologist to find out whether she has hearing loss. It’s important to follow up quickly to get the information you need to support your baby’s development. Find out more about hearing tests for babies.

Screening for congenital heart defects

To screen for heart problems, the amount of oxygen in your baby’s blood is measured. Also known as pulse oximetry (or “pulse ox”), the test involves putting painless sensors on your baby’s hand and foot for a few minutes.

If the initial test shows low blood oxygen, your baby will be tested again one and two hours later. If the pulse oximetry test still shows a low blood oxygen level, he may be given an echocardiogram. He may also be referred to a pediatric cardiologist for more tests, such as an EKG or a chest X-ray.

Newborn metabolic screening

Sometimes called a PKU test, this blood test screens for metabolic, genetic, and endocrine disorders. Your baby receives a quick needle prick on one heel to provide a few drops of blood needed to screen for certain disorders. You can hold and comfort your child during this process. The blood is put on a paper card and sent to a state laboratory for analysis. The results will be sent to the hospital or to your baby’s doctor. The doctor will contact you about next steps if the results show any cause for concern.

Disorders commonly tested for include:

  • Phenylketonuria (PKU). An inherited disease that affects the body’s ability to metabolize a type of protein.
  • Congenital hypothyroidism. When babies are born with low thyroid hormone levels.
  • Galactosemia. A life-threatening disorder that prevents babies from metabolizing a type of sugar in milk.
  • Sickle cell disease. A severe form of anemia.
  • Maple syrup urine disease. Affects the body’s ability to process proteins called amino acids.
  • Homocystinuria. An enzyme deficiency that can lead to multiple health problems.
  • Biotinidase deficiency. Another type of enzyme deficiency that can lead to severe acid buildup in the body.
  • Congenital adrenal hyperplasia. An inherited disease of the adrenal glands.
  • Medium chain acyl-CoA dehydrogenase deficiency (MCAD). Can lead to sudden infant death and serious disabilities.

When and where will my baby have newborn screening tests?

If you give birth in a hospital, the medical staff will handle the hearing and heart screenings, and draw blood for the other tests to send to a lab for analysis.

If you and your baby leave the hospital within 24 hours of birth, you might be asked to return in a week or two to finish the necessary testing.

If you deliver your baby at home, your midwife or doula may be qualified to do the hearing screen and blood test. Otherwise, take your newborn to a local hospital, clinic, or healthcare provider in the first few days of life to have blood drawn for screening, and for the newborn hearing test.

If your baby is born prematurely, has low birth weight, or is ill, she will still be screened, but she might need a special screening process, which her doctor can outline for you. For example, a blood sample may need to be taken more than once.

When will I get screening test results?

The time it takes to get results varies. Your baby’s doctor will receive the results and talk to you about them.

Newborn hearing and heart defect screening results will be available before you leave the hospital.

Newborn metabolic screening results typically take one to three weeks.

If results are normal, you usually won’t hear anything. But if you want to confirm this, contact your baby’s doctor. The results should also be in your child’s medical records by his next well-baby visit, so you can review them then.

What if my baby’s newborn screening results aren’t normal?

If your baby’s test results fall outside of normal range, don’t panic. It means further testing is needed, but your baby doesn’t necessarily have a disorder.

Sometimes a baby may have a positive result if the test was taken too soon, if not enough blood was collected, or – with the newborn hearing screening – if your baby has fluid in the middle ear. A positive result could also mean that your baby is a carrier of a condition (like sickle cell anemia or cystic fibrosis) without having the condition herself.

If something is wrong, it’s better to find out as soon as possible. Most conditions can be improved or completely controlled with fairly simple measures, such as medications or monitoring your child’s diet. If left untreated, however, many of the conditions can have severe consequences, ranging from intellectual disability to organ damage, and can even be fatal.

Can I choose which newborn screening tests my baby gets?

It depends. Some states allow parents to opt out of tests for religious or other reasons. In other states, testing is mandatory. The government believes testing is so important to your child’s health that you don’t have a legal right to refuse. Ask your healthcare provider what the rules are where you live if you’re concerned.

If you’d like additional testing, many states offer supplemental newborn screening tests (beyond what is legally required) for an additional fee. Health insurance usually covers additional screening, but it’s good to verify your coverage beforehand.

Talk to your baby’s doctor about your options. For example, the doctor may suggest extra tests if there’s concern about a certain condition that runs in the family.

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