Every baby born in New York State must have what is commonly referred to as a “heel test.” The test is performed from a small sample of blood that is obtained by pricking the infant’s heel. This test is performed in the hospital within the first few days of a baby’s life and many parents may be unaware that the test is even being administered. In most cases, the screening test is negative and no follow up is necessary. But, sometimes the test comes back positive.
Newborn screening began in the early ‘60s when Robert Guthrie, M.D. a microbiologist at the University of Buffalo developed this method of screening. Originally the test was developed to screen for phenylketonuria (PKU), an inherited metabolic disorder. It was later adapted to screen for other diseases and its success led to the development of other testing methods for many additional diseases.
Today, New York State newborn screening tests for PKU and more than 50 other conditions including sickle cell disease, cystic fibrosis, human immunodeficiency virus and hypothyroidism.
These are serious, chronic conditions that need to be addressed immediately and often require a lifetime of careful management. Yet there may be no apparent symptoms of these disorders for the first month or two of a child’s life. Newborn screening helps with the critical early detection in the prestymptomatic phase of the disorder.
Let’s take the case of PKU. Some 300 children in the United States are born each year with this inherited metabolic disorder where the body does not have the enzyme needed to metabolize the amino acid phenylalanine. This amino acid is found in all proteins including breast milk. If the amino acid builds up in the body, as it will do if the infant has PKU, it can cause serious brain damage leading to irreparable mental retardation.
The good news is that with early detection, children with PKU can be treated with a special diet. Infants require a specialized formula which does not contain phenylalanine and as they grow must follow a strict diet. Children, and adults with PKU, need to be under the care of a metabolic specialist on an ongoing basis.
Other conditions found through newborn screening require different treatments. But in all cases early detection is just as important.
A Positive Test
It is critical for parents to understand that the heel prick test is a screening tool and not a confirmed diagnosis. The screening tests are very sensitive and can often yield a false positive result. If testing shows a mild elevation parents are directed to their pediatrician who will re-administer the test.
If the results of the test are critically high parents are told to take their child to a New York State-approved evaluation center where they will be seen within 24 hours. Fortunately, Maria Fareri Children’s Hospital at Westchester Medical Center in Valhalla is a state-designated metabolic referral center so any child from Westchester (and the rest of the Lower Hudson Valley) screened with PKU or another inherited metabolic disorder through the test would be referred locally to the hospital’s program.
So even if your child is diagnosed with PKU, or another more challenging disorder, experts are locally available to help treat and mange the condition.
David F. Kronn, M.D. is director of the Inherited Metabolic Disease Center at Maria Fareri Children’s Hospital at Westchester Medical Center. For more information, please call 877-WMC DOCS or visit www.westchestermedicalcenter.com/mfch.