Newborn Blood Screening Tests

Newborn screening is a set of tests performed on your baby 1-3 days after birth, before leaving the hospital. These screening tests check for serious disorders, particularly for certain genetic and metabolic disorders. About 1 per 1000 babies will be diagnosed with a disorder as a result of newborn screening. A baby born with one of these disorders usually does not show any symptoms right away. However, if not treated as soon as possible, these disorders can develop into serious health problems like intellectual disability and even death.

Newborn screening laboratory test

When a baby is 24-72 hours old, a few drops of blood are taken from the baby’s heel. This is called the heel prick test. The blood is usually placed on a small card. The card is sent to a laboratory where it is screened for different metabolic and genetic conditions.

It is important to know that after 5 days, some tests can no longer be screened accurately using this sampling method; therefore, the newborn screening must be done promptly.

How will I get the results of the test?

Your paediatrician caring for your newborn will be notified of the screening test results and will discuss the results with you.  The test results will take 7-10 days.

What happens if my baby has a positive screening test?

A positive newborn screening test does not mean a child definitely has the medical condition. Your doctor will order more tests to confirm or rule out the diagnosis. If a diagnosis is confirmed, your doctor might refer your child to a specialist for more testing and treatment. When treatment is needed, it’s important to start it as soon as possible. Treatment may include special formula, diet restrictions, supplements, medicines, and close monitoring.

What tests are available in FV Hospital?

1. Routine newborn screening

This test screens for 6 conditions:

• Congenital hypothyroidism
• Congenital adrenal hyperplasia
• G6PD deficiency
• Galactosemia
• Biotinidase deficiency
• Phenylketonuria.

Endocrine disorders 

Endocrine disorders occur when there is a problem with the amount of hormones (chemical messengers produced by glands) in our body.

• Congenital hypothyroidism is thyroid hormone deficiency present at birth. If untreated for several months after birth, it can lead to growth failure and permanent intellectual disability. It is detected by a high level of Thyroid Stimulating Hormone (TSH) (which is secreted by the brain to stimulate the thyroid) and confirmed by a low level of thyroid hormone in the blood.
• Congenital adrenal hyperplasia: elevated levels of 17-hydroxyprogesterone (17-OHP) in a blood test are a key indicator for diagnosing congenital adrenal hyperplasia (CAH), a group of genetic disorders where the adrenal glands cannot produce cortisol properly, leading to a build-up of 17-OHP and increased male sex hormones.

Both these disorders are managed through medications.

G6PD deficiency

G6PD deficiency is an inherited condition in which the body does not have enough of the enzyme Glucose-6-Phosphate Dehydrogenase, or G6PD, which helps red blood cells function normally. This deficiency can cause haemolytic anaemia (premature breakdown of red blood cells), usually after exposure to certain medications, foods, or even infections. This disorder is managed through the avoidance of oxidative stressors such as certain medications and fava beans.

Galactosemia

Galactosemia results when a specific enzyme (a type of protein) in the body, called Galactose-1-Phosphate Uridyl-Transferase, cannot break down galactose (a sugar found in milk). When this enzyme isn’t working correctly, galactose builds up in the body and causes health problems. This disorder is managed through dietary preventative treatment.

Biotinidase deficiency

Biotinidase deficiency is a rare genetic disorder caused by mutations in the BTD gene, which impairs the body’s ability to recycle and produce vitamin B7, also known as biotin. Biotin is an essential coenzyme in the metabolism of carbohydrates, proteins, and fats. Symptoms in infants may include hair loss, dermatitis, seizures, and others. The condition can be treated with daily supplementation of high doses of biotin.

Phenylketonuria (PKU) 

Phenylketonuria is caused by a genetic mutation leading to a deficiency of the enzyme PAH, resulting in the accumulation of phenylalanine, an amino acid that is normally converted into tyrosine. This build-up causes symptoms such as developmental delay, neuropsychiatric issues, and light-coloured hair. There is currently no cure for PKU; to prevent complications, patients must follow a strict diet that limits foods high in phenylalanine, such as animal protein.

2. Newborn congenital metabolic disorders screening

• Metabolic disorders occur when there is a problem with how our body breaks down food into its simpler components: proteins, fats, and carbohydrates. They are grouped into 3 categories: amino acid disorders, fatty acid oxidation disorders, and organic acid disorders.
• 73 metabolic disorders will be screened in this panel, which are rare but can be life-threatening if dietary preventative treatment as well as medication are not administered early in life.