What is the Heel Prick Test?

photo of baby's heel

This is a test that is performed on your baby that no-one really talks until after you’ve had your baby. At this point it comes as a bit of a shock to think of someone drawing blood from your beautiful newborn baby’s heel.  So what’s it for?

The Heel Prick Test is the casual term for the test: NBBSS (New Born Blood Spot Screening). It is sometimes referred to as the PKU, which is an abbreviated term for one of the conditions it screens for: Phenylketonuria.

This test is done by your midwife on the ward, or by the Public Health Nurse after discharge. Who does it depends on when your baby was born and how.  Babies born by C-Section often have it done prior to discharge as they are usually in hospital longer than babies born vaginally, who will have it done at home or in the PHN clinic.  Either way, the test must be done after the baby is 72 hours old but before the baby is 120 hours old. Therefore it is a narrow window of opportunity, and both hospital and community health care staff are very vigilant about ensuring this test is offered on time.

The NBBSS is a National Screening Test, which means all babies born in Ireland have this test done, unless their parents opt out (which is extremely rare).  Parents are given all the information they need, but often it is when they are already exhausted and overwhelmed.  Knowing about this test prenatally may help prepare you for it.  It is an extremely important screening test.

The NBBSS tests for 8 conditions:

  • Phenylketonuria
  • Homocystinuria
  • Maple Syrup Urine Disease
  • Classical Galactosaemia
  • Medium chain Acyl CoA Dehydrogenase Deficiency (MCADD)
  • Glutaric Aciduria type 1(GA1)
  • Congenital Hypothyroidism
  • Cystic Fibrosis

These conditions are very rare, and rarely detected, but early detection and treatment of these conditions can prevent significant handicap and premature death (HSE 2021).  See the link at the end of this blog to learn more about these conditions.

How is the test performed?

Heel Prick Test

The person who does your test, will discuss it with you in advance to make sure you understand what the test is for and what is involved. You will be asked to sign your consent on a small white card, and given a carbon copy (receipt) to keep. This card has 4 circles on the end of it, which must be filled with your baby’s blood.  Mostly it only takes 1 prick to get the blood needed, but sometimes it can take up to 3, which can be distressing for parents. Some baby’s become very upset, while others sleep through it, with a mild whimper.

The Nurse/Midwife will take the sample as per his/her training. The sample must air dry for over 2 hours. It is then sealed in a special envelope, taken to the Post Office, register posted and sent to Temple Street for testing.

If the test is clear, the PHN will receive a printout about 4-6 weeks later and you will be informed of the result at the 3 month check. Basically no news is good news when it comes to the Heel Prick Test.

Sometimes, the PHN may be asked to repeat the sample as it may have become contaminated or there wasn’t enough blood taken. This is rare also. If anything is detected on the test, the National Newborn Bloodspot Lab will contact the designated Liaison Nurse in the Maternity Hospital who will contact the parents to explain the finding and organize further testing.

Tips for parents

newborn feeding through heel prick test

  • Parents are often advised to put 2 socks on their baby’s feet to help warm them, as a warm foot means increased blood flow to the area. However, double socks rarely if ever warm a baby’s foot. It is better to hold baby in one arm and place baby’s heel in the palm of your other hand, skin to skin, and enclose the foot. Then cover you both with a warm blanket. Do this for 15-20 mins and the heel is usually lovely and warm and ready.
  • When holding your baby keep your baby’s head up high, with their feet dangling lower, to encourage blood flow to the foot via gravity.
  • Breastfeeding, and non-nutritive sucking (on a finger or soother) while the sample is being taken may reduce your baby’s pain and distress, although as I said previously some baby’s show very little signs of distress.
  • If you feel upset at the thought of seeing your baby potentially upset, ask your partner to hold your baby for the test and go to another room.  Everyone is different and it is totally fine to not want to see your baby upset.
  • Ask plenty questions from whomever is performing this test. They will be happy to answer them and put your mind at rest.

For further information on the 8 conditions tested for and the entire process please check out: https://www.hse.ie/eng/health/child/newbornscreening/newbornbloodspotscreening/practicalguide.pdf


HSE (2021). Information given to parents. (Online). http://www.newbornscreening.ie/. [Accessed 05/02/2021].

newborn heels surrounded by mum and dad