Newborn tests in New Zealand: heel prick and hearing screening

Two different tests, two different windows

New Zealand offers every newborn two screening programmes in the first weeks, and they are frequently confused. The heel prick is a blood test done in the first days for metabolic and other treatable disorders. Hearing screening is a painless sound test done in the first month. Different tests, different timing, different people doing them.

Neither of these is antenatal screening. The blood tests and scans you had while pregnant estimated risk before birth. These two look at the baby who has arrived.

The heel prick test

The Newborn Metabolic Screening Programme is the formal name; almost everyone calls it the heel prick or the Guthrie test.

When it is done

The blood sample is taken when your baby is 24 hours old, or as soon as possible after this, but before they are 72 hours old. That window is not arbitrary. Some of the markers being measured are unreliable in the first hours of life, and delaying past 72 hours delays the treatment that the whole programme exists to trigger.

If your baby is born at home or you go home very early, the sample is still taken in that window — it can be done at home as well as in hospital.

How it is done and by whom

Four small drops of blood are collected onto a special card. The sample is taken by your lead maternity carer or midwife, or by a trained blood taker. Feeding your baby, holding them skin-to-skin, or breastfeeding during the sample all reduce distress, and it is reasonable to ask to do this.

What it screens for, and what it costs

The programme screens for over 20 metabolic disorders from that single spot of blood, including phenylketonuria, cystic fibrosis and congenital hypothyroidism. It is free for all eligible babies born in Aotearoa New Zealand.

Almost all babies with these conditions look completely healthy at birth and have no family history. That is precisely why the test is done on everyone rather than on babies who seem unwell.

Newborn hearing screening

Hearing screening is offered separately, through a regional screening provider.

When it happens

Screening should ideally be completed by the time your baby is one month old, and babies can be screened up to three months of age. All districts offer it to all babies, whether they are born in hospital or at home, and it is free for every eligible baby.

What the test involves

It is done while your baby sleeps and does not hurt. A trained screener places small sensors on the forehead and around the ear area, then plays soft clicking sounds through a cushion held over one ear at a time. A computer measures whether the ear and the hearing pathway are responding to sound.

If the result is not clear

An unclear result is common and usually means nothing more than fluid, movement or background noise. Your baby may simply need a second screen.

If hearing loss is suspected after that, your baby is referred to an audiologist for diagnostic testing, ideally by the time they are three months old. If hearing loss is confirmed, clinical and educational support can start by the time they are six months old. That timeline is the reason the whole programme is front-loaded into the first month: early support has a measurable effect on language development, and every month lost is difficult to recover.

Options at that point can include hearing aids, cochlear implants, sign language instruction and genetic counselling, depending on the cause and degree of loss.

Consent, and declining

Both programmes are offered rather than imposed, and you will be asked. If you are unsure, the useful questions are what the test would find, what would be done about it, and how quickly. For both of these programmes the answers are strong: the conditions are treatable, and the treatments work substantially better when started early.

If you decline and later change your mind, say so promptly — both tests have age windows, and both become less informative or harder to arrange once those windows pass.

Getting your results

Results from the heel prick go back to your lead maternity carer. Occasionally a repeat sample is needed because the first one was insufficient or unclear; that is a sample problem, not a result, and does not mean anything is wrong. Hearing screening results are usually given to you at the time or very shortly afterwards.

If you have not heard anything and want confirmation, ask your midwife or your Well Child Tamariki Ora nurse directly rather than assuming no news is the same as a recorded result.

Keep a note of when each test was done. Babies who are born early, are unwell, spend time in a neonatal unit, or have had a blood transfusion sometimes need their screening repeated or rescheduled, and the dates are easy to lose track of in that situation. If your baby was transferred between hospitals, ask explicitly whether both screens were completed, because handovers are where tests most often get missed.

Where to get help

Your lead maternity carer is the first point of contact for the heel prick and for chasing results in the first six weeks. After the handover, your Well Child Tamariki Ora provider or general practice can follow up. The National Screening Unit publishes the programme information for both newborn metabolic screening and universal newborn hearing screening, including what happens at each step and how to withdraw a sample from storage.