Neonatal screening: what it is, what it is for, how to do it


  • 1 What is newborn screening for?
  • 2 When newborn screening is done
  • 3 What diseases can be discovered with newborn screening
  • 4 Metabolic screening and early diagnosis
  • 5 How metabolic screening is done
  • 6 What happens if newborn screening is positive

After the joy of the baby's birth, there is a first moment that puts a bit of anxiety and adrenaline on all new mothers. This is the time when a nurse comes into the room and takes the baby with her to take him for newborn screening. It looks like a small pinprick on the heel, but its importance is truly vital. So let's see what newborn screening is, what it is used for and how it is performed.

What is newborn screening for?

Newborn screening is done to diagnose some very serious congenital metabolic diseases (ie present from birth and hereditary), but which if diagnosed early can be treated even before giving symptoms. It is estimated that 300 children are affected each year in the country.

When newborn screening is done

Metabolic screening is a test that is compulsorily performed between 48 and 72 hours of life of the newborn, usually before discharge from the hospital. 

What diseases can be discovered with newborn screening

Since the end of 2022, thanks to a national law, newborn screening has been strengthened: before this standard, the test was used for the diagnosis of only 3 diseases (i.e. phenylketonuria, hypothyroidism and cystic fibrosis), while now the number has been expanded at about 40. There is therefore talk of expanded metabolic screening and is now offered in all regions and countries.

The diseases searched for through this very simple examination are of an endocrine and metabolic type and are hereditary. These are serious diseases which, if not recognized early, are often fatal. In other cases, affected children live to adolescence, but with very important disabilities. In fact, the damage caused by these diseases is mostly borne by the central nervous system and is irreversible.

Metabolic screening and early diagnosis

Early diagnosis is of enormous importance in avoiding consequences on the child's health. Discovering these pathologies in the asymptomatic phase allows you to set the most appropriate pharmacological and / or dietary treatment early. In other words, early detection can save these children's lives.

Newborn screening makes it possible to diagnose diseases that are caused by the lack of a particular enzyme without which potentially toxic substances, the so-called metabolites, accumulate in the blood. Those that are discovered with screening belong to aminoacidopathies, organic acidurias and defects in beta oxidation of fatty acids. They seem difficult big words, but they all say the same thing: "getting them out" soon can make a difference.

How metabolic screening is done

How is metabolic screening performed? A few drops of blood are drawn from the baby's heel. Rest assured: he will only feel a small sting. The test is done 48-72 hours after delivery, which is when the metabolites in the blood have stabilized. That is why it is not done immediately. The blood is smeared on a card and then analyzed. 

What if the newborn screening is positive

If the metabolic screening is successful, the parents are called back from the hospital for a second, more in-depth test. If confirmation of the diagnosis arrives, therapy is started immediately, which consists of dietary changes and the administration of drugs and / or vitamins. Don't be alarmed though: it can happen that it is also a false positive. 

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