New York Nursery Nurse Discusses Newborn Screening and PKU

Posted on: February 20, 2014

Why Will My Newborn Get a PKU Screening?

By Martha Zavras, RN III, Northern Westchester Hospital

Northern Westchester Hospital maternityIf you, a family member, or close friend is pregnant, it is important to know that your newborn will be screened for several serious medical conditions, as mandated by New York State. Among the conditions screened is PKU. What is this blood test for, and what do the results mean for your new baby and your family?

As a Nursery nurse, I often administer the PKU test to newborns, also explaining to parents why it must be given so early in life. PKU is the abbreviation for phenylketonuria, a metabolic disorder. In New York State, the PKU screen, which is a simple blood test, also screens for many other disorders, including thyroid problems and some types of anemia.

It’s important to know that infants with PKU, or any of the medical conditions identified during newborn screenings, may appear to be healthy at birth. However, if left untreated, these conditions can cause mental retardation, slow growth, or result in death. Although none of the disorders can be cured, their serious effects can be lessened — and often prevented completely — if medical treatment or, in the case of PKU, a special diet, is started right away. The tremendous value of a rapid response, in these cases, is why New York State mandates newborn screenings.

Blood test results are sent directly to your pediatrician’s office, and parents are contacted by the pediatrician if a disorder is indicated. Ultimately, the results of the screenings can alert the doctor to the need for special care before a baby becomes ill – their true, invaluable benefit.

That is why, if your pediatrician recommends a re-test — in the form of another blood test — or a special formula or treatment, it is essential to act without delay.

What is PKU?

PKU, or phenylketonuria, is an inherited metabolic disease. Babies with PKU are missing an enzyme that is needed to break down an essential amino acid called phenylalanine. Phenylalanine is found in foods that contain protein: Milk, meats, and soy to name a few.

Without the enzyme, levels of phenylalanine and other closely-related substances are not metabolized and build up in the body. These elements are harmful to the central nervous system and cause brain damage.

The PKU screen tests for this metabolic disorder. When detected early, it can be treated with simple dietary changes. Similarly, hypothyroidism, another condition revealed by the PKU blood test, can be treated by medication and monitoring by an endocrinologist.

Given within 24 to 48 hours of life, the PKU screen consists of taking blood from the newborn’s heel, as this area has a fatty pad that makes the test less uncomfortable. The heel is typically warmed before the blood draw, which increases blood flow, making it easy to obtain the specimen.

You can find detailed information about the complete panel of newborn testing on the website:  I encourage you to become familiar with newborn screenings – how and when they are performed, and what they show. Knowing more about how and why your newborn is screened will reassure you, and put you in the best position to take immediate and effective action, if necessary.