Newborn Screen

My baby had an abnormal Cystic Fibrosis Newborn Screening Test: Before taking your baby home from the hospital, a small amount of blood was taken from their foot for newborn screening. Newborn screening is a statewide program to identify babies with specific health problems. Babies are screened for these problems because the earlier a child is diagnosed and treated, the healthier the child is. You may have received a pamphlet from the hospital or your doctor describing the diseases screened for in your state.

Children's Specialists of Florida Pulmonology and Sleep Medicine

Why does my baby need a test for Cystic Fibrosis?

One of these tests screened for is cystic fibrosis (CF). Your baby's screening test showed that your baby might have CF. However, a second test called a sweat test or a genetic test is needed to diagnose CF. The sweat test will measure how much salt is in your baby's sweat. This test is the best way to diagnose CF. Too much salt in the sweat means a person has CF. Most babies who have to have a sweat test because of an abnormal newborn screen do not have CF, but it is essential to be sure they do not. This should be done at a CF Foundation-accredited care center. You can find the center closest to you and more about sweat testing on the CF Foundation's Website ( CF causes people to have salty sweat, breathing, and digestive problems. Those with CF need to be seen by particular CF health care providers. When CF is diagnosed early, the baby can start to receive care to help keep them healthy. Your baby may have a genetic test instead of a sweat test to determine whether they have CF. A blood test can do genetic testing. A person has to have two abnormal CF genes or CF mutations to be diagnosed with CF.

What can I Expect Before and During the Sweat Test?

A CF sweat test should be done at a CF Foundation accredited care center. This test can usually be done within a few weeks from the time the newborn screening test results are reported to your baby's doctor. On the day of the sweat test, do not use any lotions, creams, or moisturizing soaps on your baby's arms or legs. Bring an extra blanket or sweater and hat to keep the baby warm so thatthey will sweat during the test. The sweat test takes about one hour from start to finish. A special gel is applied to the baby's skin on their arms or legs, and small patches with wires are used for about 5 minutes to cause the baby to sweat. The skin may feel warm and tingly while the patches are in place, but it is not painful. The sweat is then collected on a gauze nasty or disk. After about 30 minutes, the gauze or disk is removed, and the accumulated sweat will be tested in the lab.

What do the Results Mean?

The sweat test results should be available to your doctor by the next day or two. There are four possible results: Negative result: This means that an average amount of salt was found in the baby's sweat. It is scarce for a person to have CF if the sweat test result is negative. Positive result: A positive sweat test means that the baby probably has CF. A second sweat test should be done, and an appointment should be made at a CF Foundation accredited care center specializing in treating people with CF. Your doctor can refer you to the closest CF Center, or you can find a care center on the CF Foundation's website Borderline result: Sometimes, the sweat test result will be positive or negative. The baby should have another sweat test or a genetic test and be seen at a CF Foundation-accredited care center. Quantity Not Sufficient (QNS): This means that there was not enough sweat on the gauze to measure the amount of salt, the baby will need to return on another day to repeat the sweat test.

My baby was found to have one CF gene or a CF carrier. What does this mean? Some babies whose newborn screen is positive or abnormal for CF do not have the disease, but they are carriers of one CF gene mutation and do not need special medical care. However, if your baby is a CF carrier, you or your partner are carriers of the CF gene mutation. If both of you are CF carriers, you could have a baby with CF in the future. This fact sheet My Baby is a CF Carrier: What does that mean for my baby? What does that mean for me? talks about what it means to be a carrier of a CF gene mutation. It is available from the CF Foundation ( If you are not sure if your baby is a CF carrier, ask your baby's health care provider.