Heel prick: What is it?

heel prick

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When a baby is born, the medical personnel attending the delivery, in addition to making sure that the mother is in good condition after giving birth, have to perform some tests on the newborn. Thus, if any disease has developed, the sooner it is known, the sooner treatment can be started (if necessary). It should always be kept in mind that early detection can make a huge difference to a person’s quality of life or even their life. That is why infant or newborn screening is so important and should be performed whenever possible. One of them, and one of the most common, is the heel prick test. Below we will explain why it is called this way, what it is used for and how the results should be interpreted.

What is the heel prick test?

The heel prick is the popular name for a test called early detection or newborn screening. It is part of the 3 tests that are performed on all newborns, along with the Apgar test and the hearing test. The purpose of this test is the early detection of hereditary metabolic diseases. The aim is to diagnose any disease, if it exists, before it begins to show its symptoms in the patient. This test is performed in the hospital itself within 48/72 hours after the birth of the baby.

The diseases detected by this test are the so-called congenital diseases, which are present from the moment of birth. For this reason, early detection can help to control the development of the disease and improve its evolution, since those included in the early detection program through heel prick tests can be treated. This, thanks to the knowledge of the presence of the disease in the organism, can prevent or reduce the symptoms and lesions that would occur without the appropriate action.

The heel prick test is a neonatal screening, so it is not a diagnosis as such. If any test result is outside the normal range, diagnostic confirmation through analytical tests and clinical assessment of the newborn will always be necessary. If at that time a suspected disease is confirmed, early treatment of the pathology(ies) discovered will be started.

Therefore, we want to clarify that the heel prick is routine and does not mean that the baby has any disease. It only serves to rule out and prevent, but when dealing with diseases, proceeding with caution is one of the best practices. However, congenital metabolic diseases (which the heel prick test detects) are rare, but may be present at birth.

This test is highly recommended, but not mandatory. After being informed, parents and/or mothers must sign a form authorizing the test to be performed on their baby.

What diseases does it detect?

The diseases detected by the heel prick test are endocrinological, metabolic, blood and immunodeficiencies. Metabolic diseases are the main ones screened for by this newborn screening and are caused by the malfunction of a protein due to a mutation in the DNA. The number of diseases that can be diagnosed with the test depends on the autonomous community in which the patient is located.

Until 2013, some communities could study only 5 possible diseases, and others up to 30. Therefore, to avoid this difference and guarantee equal treatment for all babies, the Ministry of Health established a series of mandatory diseases that are part of the heel prick test:

  • Congenital hypothyroidism.
  • Cystic fibrosis.
  • Phenylketonuria.
  • 5 more disorders of amino acid metabolism.
  • 8 disorders of organic acid metabolism.
  • 6 disorders of fatty acid metabolism.
  • Sickle cell disease.
  • Severe combined immunodeficiency.

This screening can also detect healthy babies with a genetic alteration related to a disease that they will not develop (carriers), so it will not affect them. Even so, it is always good to know what alteration exists, in order to intervene if necessary. Diseases that are not part of the program can also be diagnosed. In this case, the same procedure is followed as for other diseases.

What does the test consist of?

The heel prick test requires a blood sample from the heel, which should ideally be taken 48 hours after birth. This test is therefore performed in the maternity ward of the same hospital where the baby was born. To obtain the sample, a shallow prick is made on the side of the baby’s heel and a few drops of blood are collected. These are impregnated on a special absorbent paper, approved on both sides.

This paper is sent to the laboratory for analysis. Along with the collection of the sample, the data of the family and the newborn are also enclosed in a card. This will be used to send the results to the family and, if necessary, to contact them.

The nursing staff is in charge of performing this test. The lancets they use are designed to generate an exact small cut, which causes minimal pain sensation to the baby. The collection of the blood sample takes only a few minutes. The aim of the test, in addition to the blood collection, is to prevent pain in the baby at all times. Therefore, it is advisable for the mother to hold the baby while the prick is performed, as it makes the baby show less distress. The baby’s leg is placed below the baby’s heart to increase venous flow.

If the mother cannot be with the newborn, putting a pacifier on the newborn reduces the scores on the pain stairs. The best scenario for the infant to suffer as little as possible is when breast milk or sucrose administration is used in conjunction with suctioning and restraint. Possible sequelae are residual pain and slight bruising around the puncture site, which disappears after a few days.

Heel prick test results

The paper with the blood sample, as mentioned above, should be sent to a neonatal screening laboratory for analysis of the sample and screening for diseases. Each of them has a range of normal results. The laboratory will be responsible for notifying the family using the following procedure:

  • The results are within normal limits (negative). If all is well, after 30-40 days the family is informed of the result by letter. The letter arrives at the home address in the mother’s name with the data collected on the screening form. The family is notified of the normal results and the screening program is terminated.
  • The results are not within normal limits (positive). We have clarified this before, but it needs to be repeated. This does not mean that the baby has the disease. It is only a screening, so further testing will have to be done to confirm or rule out the diagnosis. The laboratory will call the family urgently to re-sample or to call them to the clinical diagnostic and follow-up units. There they will continue with further diagnostic procedures to confirm or rule out the suspected disease.
  • Samples cannot be tested or are insufficient. This may occur because the specimen has been contaminated in some way and could not be tested correctly. The same test will simply have to be performed again.

Special cases

This test cannot be performed in all cases. In fact, it is contraindicated in infants whose heels (both) are edematous, injured or infected. When the test cannot be performed on the heel itself, venous blood collection is recommended.

If a newborn is admitted to the ICU, it is necessary to assess the harm/benefit of performing this heel prick or whether it is better to take an arterial/venous blood sample (if they have an umbilical catheter).

In newborns requiring transfusion, the test should be performed, whenever possible, prior to transfusion, even if the infant is less than 48 hours old. The test should be repeated when appropriate according to the type of transfusion.


The heel prick is one of several tests performed on newborns to detect possible congenital diseases. It is not a diagnosis as such, as it does not indicate that the baby has the disease. But it can help to ‘raise the alarm’ and perform the necessary tests for the correct diagnosis. Thanks to this test, larger sequelae can be avoided which, without this early detection, could have been missed.

All that is needed is a blood sample from the newborn’s heel (48/72 hours after birth), which is placed on a blotting paper specifically designed for this purpose. This will be sent to the laboratory for analysis and subsequent communication of the result to the family.

Therefore, from Ambar Lab, we strongly recommend the performance of this test. Our laboratory offers this and many other tests, which you can see on our catalog.. If you have any doubt or specific question, you can contact us. Our team will be pleased to assist you.

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