Newborn Screening: The Good, The Bad, and The Incredible Potential

I’ll never forget the day I met a man with untreated PKU. PKU, also known as phenylalanine hydroxylade deficiency, is a genetic condition that occurs when someone cannot process the amino acid phenylalanine. This is a protein component found in meat, fish, eggs, milk and cheese and is even added to things like to gum and diet soda. Although physical symptoms may not be present, irreversible brain damage and intellectual disability may occur if treatment is not begun in the first 2-3 weeks of life.  This man, who I met in a metabolism clinic, was nonverbal and restrained to a wheelchair with straps. He lived in a group home and had no family. He struggled to free himself from the wheelchair (even though he did not know how to walk). He slapped at the doctor trying to listen to his heartbeat. He could not speak and communicated with sounds that I can only describe as barking. He looked miserable. The very next day, in the same metabolism clinic, I met a delightful 8-year-old boy who was also diagnosed with PKU. But unlike the man, this child was diagnosed at one week old through the state newborn screening program and had been on treatment and adhering to a special diet his whole life. And as long as he and his family continue to diligently follow his doctors’ recommendations, the boy’s future is nothing but optimistic.

This is why we have newborn screening.

 Here is great video showing the difference between adults with treated and untreated PKU.

Newborn screening is a state run public health service designed to screen all babies for certain serious genetic disorders. This program began in the 1960s when Dr. Robert Guthrie developed a blood test that could test for one condition: PKU. Today, all babies born in the United States are screened for PKU and a variety of other genetic conditions within the first 48 hours of life. The goal is to identify all affected babies before symptoms are present,  so that doctors can start treatment early and hopefully improve the long term quality and length of life. The test is run on a few drops of blood taken from pricking the baby’s heal and may also include a hearing test and/or pulse oximetry to determine the oxygen level in the blood.

I am so passionate about newborn screening and truly believe it is one of the most amazing parts of our healthcare system. But when you see so much value and so much potential in a program, you want that program to be the best. Because of this, I also find newborn screening very frustrating, primarily because of the vastly different, unfair experience that babies can have depending on the state in which they are born.

Each state’s public health department determines what conditions will be included in their newborn screen. Generally speaking, a condition has to meet the following criteria to be considered for newborn screening:

  1. The condition has to be common enough in the population to justify screening all newborns.
  2. The condition can be detected within 48 hours of birth through testing, but would not likely be diagnosed by a physician’s physical exam.
  3. An affordable testing option specific to the condition exists and has a high detection rate.
  4. There is a proven benefit to pre-symptomatic treatment and intervention.

States also receive some guidance about what conditions should be screened for. Along with the Secretary of the U.S. Department of Health and Human Services, a group called the Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC) created and updates a recommended list of conditions. This list, the Recommended Uniform Screening Panel, includes 34 core conditions and 26 secondary conditions. States do not have to follow these recommendations, and in fact, Michigan and Pennsylvania are the only states that screen for all 34 core conditions.

After spending several hours looking up all the states’ newborn screening programs, I compiled the chart below.  For  number of conditions screened for, Tennessee takes first place with 69 conditions (but is missing one of the 34 recommended) and Kansas and Rhode Island are tied for last with only 30 conditions. (Information obtained from

I can understand if this big testing inequality frustrates you, because it definitely frustrates me.  And that is really why I am sharing this information- I want to call more attention to the situation. It’s wonderful that our states even test for anything. I cannot say that enough. We are so fortunate to have these programs. But if I had a baby who had a condition that my state didn’t test for and another state did, I know I would never stop lobbying for my state to step it up, knowing how different my child’s life would be if he had been born on the other side of the state line. Fortunately, we do not need to wait for something terrible to affect us personally to get involved and advocate for better testing. I encourage you all to look into your state’s newborn screen and let it be known that you know how they compare and where they could be doing better.

Outside of state run newborn screening, there are also ways that you as an individual can investigate risks for treatable genetic conditions in your children. One option is a supplemental newborn screen. Just as it sounds, this gives parents the ability to request that their children are screened for more conditions than their state tests for. There are many laboratories that offer this type of testing, but it typically requires some planning ahead and may have an additional cost to the family.

Another way to be prepared for conditions that your state does not screen for is to do carrier screening before or during pregnancy. Carrier screening is done on the parents to see if there are any conditions that their (future) children are at increased risk for. The majority of conditions on the newborn screen are autosomal recessive, meaning both copies of the gene need to be non-functional in order for a person to be affected. If a person has one non-functional copy and one functional copy, they are called a carrier and typically do not experience any symptoms. Everyone is a carrier for a few different conditions, so learning that you are a carrier is nothing to be concerned about. If a mom and dad are carriers of the same condition, however, there is a 25% chance to have an affected child with each pregnancy.

Carrier screening is supposed to be offered to every woman who is pregnant or considering pregnancy, but in my experience, many patients I have met with are completely unfamiliar. Ask your doctor or genetic counselor about the carrier screening options available at their practice. While some offices only offer carrier screening for a few conditions (per official medical society recommendations, carrier screening is available for hundred of conditions, you just may need to ask or be prepared to pay out of pocket. I have many patients who are very pleasantly surprised to learn that when not covered by insurance, even large carrier screens can only cost a few hundred dollars.

Every time I talk about newborn screening, I want to be sure to emphasis the fact that it is a screening test. This means that it is not designed to definitely determine if a person has one of the conditions or not, but rather assess if it is more likely or less likely. Just because a person tests positive for a condition on the newborn screen does not mean they are actually affected, and additional testing is done for confirmation. In fact, ~90% of positive newborn screen results end up being a false positive and the person is only a carrier of the condition. On the other hand, although unlikely, it is possible for a newborn screen to miss an affected individual and give a false negative test result.

So for all of you having babies or thinking about heading in that direction, I strongly encourage you to research and learn about your state newborn screening, its highlights and shortcomings, and what you as a parent and advocate for your child can do to fill in the gaps. And if you ever need a genetic counselor to help you navigate the complexities and options, you know I am always here to help!

Wishing you all happy, healthy babies and happy, healthy lives!


For more general information on newborn screening or to learn about your state’s specific test visit

One Response

  1. Rose Standish

    Excellent presentation blog Erin. I am going to forward to my past students, but I can’t require them to read it. Knowledge is power!!!!

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