6 things tested for in the newborn screening

newborn screening, heel prick test, Guthrie test, congenital hypothyroidism, Phenylketonuria, Maple syrup urine disease, cystic fibrosis, classical galactosaemia
newborn screening, heel prick test, Guthrie test, congenital hypothyroidism, Phenylketonuria, Maple syrup urine disease, cystic fibrosis, classical galactosaemia

Soon after your baby is born, they will be taken for their routine newborn screening which tests for a series of health conditions. This is known as the heel prick test and we explain what it is and why it is carried out.

The heel prick test (or the Guthrie test) is usually carried out within a week of your baby’s birth.

A special device is used to prick your baby’s heel collecting a sample of his blood onto a screening card. The card will be sent to a laboratory for testing, identifying babies who may have a range of rare but serious conditions.

Babies are routinely screened for six inherited conditions:

Congenital hypothyroidism (CH)

CH is a lack of the thyroid hormone and affects one in 3,500 infants. Although only a small number of cases are inherited genetically. Without treatment, CH can cause poor growth and irreversible neurological problems. It is usually treated with medication.

Phenylketonuria (PKU)

Around one in 4,000 children are born in Ireland every year with PKU. It is a metabolic disorder where sufferers have problems breaking down the amino acid phenylalanine. If untreated, the build-up of phenylalanine in the brain can be toxic, resulting in brain damage. The condition is treated with a controlled diet and most children go on to lead a normal, healthy life.

Maple syrup urine disease (MSUD)

Approximately one in 125,000 babies will be born with MSUD. It gets its name from the fact that the urine and earwax of sufferers can smell like maple syrup. Babies born with MSUD can’t break down certain amino acids, which results in a toxic build-up in the body. In its most severe form, MSUD can result in damage to the brain. However, the disease can also be controlled by diet.

Classical galactosaemia

Sufferers of this condition have the inability to break down galactose (a sugar found in human and cows’ milk). It affects one in 19,000 babies. This disease, however, is more common in the Traveller community where it is present in one in 40 babies. For this reason, babies born to Traveller parents are screened at birth and routinely offered a galactose-free milk solution until test results are known. If this condition is left untreated, it can cause liver damage and may even be life-threatening. Classical galactosaemia can also be controlled by a strict diet.

Cystic fibrosis (CF)

This condition affects the internal organs by clogging them with thick mucus. It mainly affects the lungs and digestive system, making it difficult for sufferers to breathe and to digest food. CF affects one in 1,500 babies and it is treated with medication and physiotherapy. Early detection of this disorder helps improve quality of life and can reduce time sufferers spend in the hopital.


This is an amino acid disorder where methionine is not broken down properly causing it, along with the amino acid homocystine, to build up in the blood. If gone untreated, Homocystinuria can affect the eyes, bones, heart, and blood vessels, and cause growth and learning delays in children.

The Test Results

The heel prick test results are usually known within a week, but normally you will only be contacted directly if there’s a problem. The conditions tested for are rare and for most babies, results will come back normal.

If your baby is found to be at risk of having one of these conditions, then he will be referred to a specialist unit where his condition will be diagnosed and managed. If you are concerned or have a family history of any of these disorders, speak to your GP or midwife.

Disclaimer: This is a guide and not a substitute for medical advice. You should always consult a doctor for further information.

maternity & infant

Originally posted 2018-02-19 14:56:10.