Dr. Bob: We are about to have our first baby. I have heard my friends talk about the blood test that is done on the baby to screen for various problems. Do I have to have it done? Does it hurt?
Answer: I am so glad that you asked. Since I spent my career as a pediatrician and a medical geneticist, newborn screening is near and dear to my heart. Yes, please have it done. Let me explain.
The advent of newborn screening for severe potentially lethal genetic conditions started back in the 1960s. With a very simple blood spot test, phenylketonuria (PKU) could be detected. The condition, when untreated, leads to profound intellectual disability (formerly known as mental retardation) and seizures. The treatment involves dietary restriction of certain protein building blocks or amino acids. The treatment works and is a dramatic example of how scientific discoveries can prevent disabilities and potentially save lives. PKU occurs about 1 in 15,000 births so we would expect 4 babies a year to be born in SC (around 60,000 live births/year) and detected and treated before adverse effects occur.
The blood test is a simple prick of the heel and drops of blood are put on filter paper that is dried and sent to the state lab for analysis. The transient crying is easily soothed.
In 2024, there are now 56 different conditions that are screened. That is amazing! Fifty-six different conditions that are severe in nature and potentially treatable are screened. What started as testing that was purely looking at problems of body chemistry (inborn errors of metabolism), multiple other problems are tested. For example, problems of the thyroid gland occurring in about 1 in 3,000 births are detectable and preventable. Problems of hemoglobin (the oxygen carrying protein in red blood cells) leading to sickle cell disease are screened for and can be treated early. Problems of the lungs and intestines (cystic fibrosis [CF]), brain and spinal cord, nerves and muscles, immune systems and other conditions are now tested in the panel.
One requirement for conditions to be part of the newborn screening panel is that treatments are available. Conditions are not screened just to be identified. Some type of therapeutic intervention must be present for a test to be done.
In addition to the blood test, two other tests are done. All babies are screened for severe hearing loss and congenital heart disease since early intervention is so important. These latter two tests are a welcome addition to the newborn screening testing.
So, let me get back to your question. I would embrace the newborn screening tests. The ability to identify and potentially treat severe to lethal conditions is a triumph of modern medicine. I, of course, have to mention that the testing is not perfect. False positive and false negative results can occur at a very low rate. That is why quality control measures and constant monitoring are so important. And the treatments are not necessarily curative but potentially of significant benefit.
I have cared for children with PKU, untreated and affected and also treated and unaffected. The ability to detect and treat such a condition remains a medical miracle that occurred in my lifetime. The addition of other conditions is exciting. More will be added as science progresses and the mysteries of medical conditions are solved. Be thankful for this testing. Make sure that it gets done and be sure to check the results with your baby’s doctor.
Dr. Saul is Professor of Pediatrics (Emeritus) at Prisma Health and his website is www.mychildrenschildren.com. Contact Dr. Bob at askdrbobsaul@gmail.com with more questions