PediatricsPreventive Medicine

BABY’S FIRST TEST: Screening Newborns for Preventable Diseases

Did you know that before you brought your newborn son or daughter home from the hospital he or she had been tested for as many as eighty (80) inherited diseases? Yes, that’s correct. In some states, as many as 80 genetically-inherited diseases occurring at birth are tested for and ruled out. Each state has a law mandating specific diseases for which all newborns in that state must be tested after birth. These diseases are either inherited or are “inborn errors of metabolism” that fall into 10 categories. These are very rare disorders that are easy to diagnose. Most, however, have symptoms that are not detectable until the infant is older and harm has already been done.

Because of the devastating effects of these diseases, and because when diagnosed early, treatment that corrects the abnormality can begin and prevent those consequences, the states and federal government have developed guidelines for detection. Laws have been passed that require testing for all infants in the newborn period. State legislators in coordination with State Boards of Health and organizations of newborn care providers adopted testing protocols specific to each state.

An organization called oversees newborn testing. It is a resource guide for parents and health care professionals with regard to state-specific testing recommendations and information about the diseases. It is funded through grants and special gifts, and pays for testing when insurance denies payment. It is loosely affiliated with the U.S. Department of Health and Human Services (HHS). On their website, doctors and the public can see listed the disorders for which each state screens and learn details about those diseases

Newborn screening tests are usually done within 24-48 hours after birth while the baby is still hospitalized, and are done from small samples of dried blood (DBS-dried blood sample) obtained by heel-stick. Some tests are done later when the child is 1-2 weeks old. Babies not born in a hospital may or may not have these tests depending upon the newborn care provider and the parents.

The first of these was the PKU test. Phenylketonuria (PKU) is an inherited enzyme deficiency that leads to the build up of the amino acid, phenylalanine, which in excessive amounts, among other things, causes intellectual disability. When I started practice in 1974, it was the only test available, and every newborn had it done before being sent home. This disorder was discovered in 1934, but testing did not begin until the 1950’s. All fifty states subsequently adopted laws requiring all newborns to be tested for this preventable disease.

As time went on, more tests were developed for other inherited and preventable disorders that are also done in the first 48 hours of life or at 1-2 weeks of age. Each state has different laws that determine for which diseases newborns are to be tested. As mentioned above, there are now numerous tests for disorders you probably haven’t heard of, and I definitely haven’t seen. In fact, in forty years of practice, I never had an abnormal newborn screen.

The newborn nursery of each hospital has a testing protocol that is done without the need for a doctor’s order. These tests are done automatically, the results are kept in the infant’s hospital record and are reported to the doctor if positive (abnormal). Indiana tests for 49 different disorders, and Arizona 31. The program is called Baby’s First Test (see above) and one DBS is used to test for all of these numerous diseases.

In addition to blood testing, the delivery room nurses crede’ (cree-day) the baby’s eyes. Crede’ is a term for treatment of the eyes with medication to prevent ophthalmia neonatorum—a bacterial infection of the eyes acquired during vaginal delivery. Silver nitrate drops were used years ago, but now antibiotic ointment is applied immediately after delivery.

Also, the nursery staff screens the baby for hearing loss and makes certain no vision problems are present.

The major, more frequent disorders for which blood screening is done are as follow:

Phenylketonuria (PKU)—an inherited disease in which phenylalanine cannot be metabolized.

Can cause mental retardation. Testing required in all 50 states.

Congenital Hypothyroidism (Cretinism)—baby is born with too little or no thyroid hormone.

Leads to small stature and slow mental development. All 50 states require testing.

Galactosemia—inherited disorder in which the baby cannot metabolize galactose, a milk

sugar. Can be life threatening disease if baby drinks milk. All states require testing.

Maple Syrup Urine Disease (MUSD)—inherited disorder common in Mennonites. The baby’s

urine smells like maple syrup. The body cannot process certain proteins (amino acids). It is

life threatening in the first two weeks of life.

Sickle Cell Disease—inherited disorder in African Americans that causes anemia and crises

that can cause kidney failure, severe infections, and blood clots.

Cystic Fibrosis—genetically-acquired disorder causing thicker than normal body secretions.

It results in severe respiratory problems, frequent pneumonia, poor growth, among others.

Homocystinuria—inherited disorder causes intellectual disability and blood clots. The body

is unable to digest the amino acid methionine.

Biotinidase Deficiency—inherited enzyme deficiency that causes build up of acid in the

blood, organs, and body systems.

Congenital Adrenal Hyperplasia—babies with this disorder cannot make cortisol and thus

have blood pressure problems and trouble controlling sugar levels.

Medium-Chain acyl-CoA dehydrogenase deficiency (MCAD)—a metabolic disorder that can

cause sudden infant death or intellectual disability.

Congenital Toxoplasmosis—a parasitic disorder passed from mother to fetus that can cause

miscarriage or stillbirth and is associated with visual, hearing, motor, and cognitive

problems in the infant.

Most of these disorders are quite rare, and I doubt if you’ve heard of many of them. I have seen Sickle Cell Disease a few times during med school and residency. During a “crisis,” in which the individual’s red blood cells break up (hemolyze), the patient becomes very anemic and can go into shock and kidney failure. It can be fatal.

I also know of a child with congenital hypothyroidism. At birth her thyroid hormone level was zero. Had this gone undetected, her growth and mental development would have been affected severely. The term for this is Cretinism from which the derogatory name Cretin was derived. All it takes to treat this disorder is a daily dose of thyroid replacement hormone and her growth and mental development will continue normally.

As you can see, detection of these rare, but serious, diseases is critical to the lives of those affected. Credit goes to those brilliant medical investigators and scientists who discovered these diseases, formulated accurate screening tests, and developed effective treatments that allow normal physical and mental development and save lives. State legislatures have been responsive to the Baby’s First Test program making these tests available to every newborn.

Dr. G’s Opinion: I enthusiastically support and believe in these important newborn screening tests. Not every state tests for all of these tests. Each state has its own procedure, and as I mentioned, Indiana tests for 49 disorders and Arizona for 31. Looking at Indiana’s website, however, they list 80 diseases in 10 different diagnostic categories for which testing is done. I haven’t done newborn care since 2007 so obviously a lot has changed in the newborn screening realm. Much research is done in this area, and I suspect each time a new inherited metabolic, endocrine, or other category disorder is found, a new test is devised to be included in the list. Thank goodness for this program because of the many babies it will help to develop more normally.



Newborn Screening Expands: Recommendations for Pediatricians and Medical Homes—Implications for the System. Pediatrics 2008 Jan 1;121(1):192-203.

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