Newborn screening (NBS) is a test that can help identify certain serious health conditions in the newborn before symptoms arise. This ensures that treatment can be started as soon as possible, which can mean improved quality of life for the baby.

The newborn screening consists of three parts: blood spot screening, pulse oximetry, and a hearing test. The blood spot screening is a blood test usually done on the third day of life that helps diagnose certain congenital and metabolic conditions like congenital hypothyroidism, phenylketonuria, sickle cell disease, and cystic fibrosis.

The newborn screening test is required by all states in the US, however certain states do allow parents to refuse testing. The conditions tested for also vary by state.

How the test is done

The blood spot screening is done by collecting a few small drops of blood from the baby's heel on a special card, which is then sent to the state lab for analysis. The lab runs tests to check for the presence of multiple conditions.

When the test is done

The blood spot screening test should be done at the hospital where the baby is born, or at your home or birth center in the case of out of hospital birth. If your midwife is not trained in NBS, make sure to make other arrangements at your health center or doctor's office. It is most often performed on the third day of life but can done within the first month of life.

In the case of positive results, the family will be contacted by their healthcare provider or their state NBS program. Further testing may be indicated to confirm the diagnosis so that proper treatment can be started as soon as possible.

What conditions can be identified?

Blood spot screening can identify a variety of conditions, including:

1. Phenylketonuria (PKU)

Phenylketonuria is a rare genetic condition characterized by an accumulation of phenylalanine in the blood. In this condition, the enzyme responsible for the breakdown of phenylalanine is absent or deficient.

High levels of phenylalanine, which is also found in eggs and meat, can be toxic to children and result in impaired neurological development.

How it is treated: The treatment of PKU consists of controlling and decreasing levels of phenylalanine in the blood, which is done by avoiding certain foods high in phenylalanine, like meat, eggs, nuts, and soy.

Because the PKU diet can be very restrictive, it is important that the child is followed by a nutritionist in order to prevent nutritional deficiencies.

2. Congenital hypothyroidism

Congenital hypothyroidism is a condition in which the baby's thyroid gland does not produce enough thyroid hormones, which can interfere with normal development and lead to serious health problems including intellectual disability.

How it is treated: Treatment of congenital hypothyroidism begins as soon as the diagnosis is made and typically involves taking thyroid medications to increase hormone levels in the body, helping to ensure healthy growth and development.

3. Sickle cell disease

Sickle cell disease is a genetic condition characterized by an alteration in the shape of the red blood cells, which reduces their capacity to transport oxygen throughout the body and can lead to complications like organ and tissue damage.

How it is treated: Depending on the severity of the condition, the baby may require blood transfusions to help improve oxygen delivery to the vital organs.

While sickle cell disease is not curable, treatment will focus on managing symptoms and preventing complications. This may include careful monitoring and treatment of infections (like pneumonia and tonsillitis) that may arise.

4. Congenital adrenal hyperplasia (CAH)

Congenital adrenal hyperplasia is a condition caused by a deficiency of certain hormones or an overproduction of others, resulting in excessive growth, precocious (early) puberty, or other physical problems.

How it is treated: It is important to identify the cause of CAH so that hormone levels can be corrected with medication. Treatment for CAH is typically lifelong.

5. Cystic fibrosis

Cystic fibrosis is a disorder involving the buildup of large amounts of mucous, compromising the respiratory system and also affecting the pancreas. It is important for cystic fibrosis to be identified as soon as possible so that treatment can be initiated that can help prevent complications.

How it is treated: Treatment of cystic fibrosis involves the use of anti-inflammatory medications, adequate nutrition, and respiratory therapy to relieve symptoms like difficulty breathing.

6. Biotinidase deficiency

Biotinidase deficiency is a genetic disorder in which the body is unable to recycle biotin, a vitamin that is crucial to healthy functioning of the nervous system.

Babies with this condition may present with seizures, poor motor coordination, developmental delays, and hair loss.

How it is treated: In these cases, a doctor will prescribe biotin supplements to be taken for life, which will help compensate for the body's inability to metabolize this vitamin.

Other conditions

Other tests included on the newborn screening may include:

Congenital toxoplasmosis: a potentially fatal illness that can cause blindness, jaundice (yellow skin), seizures, and intellectual disability;
Spinal muscular atrophy: a rare neuromuscular disorder that affects voluntary muscle movement;
Severe combined immunodeficiency (SCID): a condition in which the baby has low levels of antibodies and low or no T cells (lymphocytes), increasing the risk for potentially life-threatening infections;
Galactosemia: a condition in which babies cannot digest the sugar present in milk, which can lead to central nervous system damage;
Amino acid disorders, a group of metabolic disorders that interferes with the body's ability to break down certain amino acids from proteins;
Lysosomal storage disorders, which interfere with cellular function;
Hyperphenylalaninemia, which involves an excess of phenylalanine in the blood that can cause changes in behavior and affect cognitive development;
Hemoglobinopathies, which are disorders affecting hemoglobin that can interfere with oxygen transportation in the body.

It is important to note that not all of these tests may be included on the screening panel for every state. Make sure to check which tests are included on the newborn screening panel for your state.