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MCADD: heel prick screening

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is an inherited condition.

Babies born in Ireland with MCADD

Around 1 in every 17,000 babies born in Ireland has MCADD.

Babies with MCADD inherit 1 changed gene from each parent.

How heel prick screening can help

Babies are checked for MCADD as part of heel prick screening. They are offered heel prick screening when they are around 5 days old. This test also checks for other conditions.

A midwife or nurse takes a few drops of blood from your baby's heel using a special device.

If the heel prick suggests your baby may have MCADD, they will see a specialist.

If their treatment starts early, your baby can have a healthy and active life.

Newborn babies can sometimes become sick and show symptoms of MCADD before they have their heel prick screen or their results. This is very rare.

Non-urgent advice: Contact your GP if

your newborn baby has any symptoms of MCADD, such as:

  • drowsiness
  • poor feeding
  • vomiting
  • low energy
  • seizures or fits

Page last reviewed: 21 September 2025
Next review due: 21 September 2028