The heel prick test, also known as neonatal screening, is a mandatory exam carried out on all newborns, normally from the 3rd day of life, and which helps to diagnose some genetic and metabolic diseases, and, therefore, if If any changes are identified, treatment can be started immediately, avoiding complications and promoting the child’s quality of life.
The heel prick test promotes the diagnosis of several diseases, however the main ones are congenital hypothyroidism, phenylketonuria, sickle cell anemia and cystic fibrosis, as they can cause complications for the baby in the first year of life if they are not identified and treated.
In May 2021, the Unified Health System approved the expansion of the heel prick test throughout Brazil, making it possible to identify up to 50 rare diseases. However, the implementation of the expanded heel prick test is only scheduled for May 2022 (1).
How is done
The heel prick test is carried out by collecting small drops of blood from the baby’s heel, which are placed on filter paper and sent to the laboratory for analysis to be carried out and the presence of changes checked.
When to do the heel prick test
The heel prick test must be carried out in the maternity ward or in the hospital where the baby was born, and is recommended from the 3rd day of the baby’s life, however it can be carried out up to the first month of the baby’s life.
In the case of positive results, the baby’s family is contacted so that new, more specific tests can be carried out so that the diagnosis can be confirmed and appropriate treatment can be initiated.
Diseases identified by the heel prick test
The heel prick test is useful for identifying several diseases, the main ones being:
1. Phenylketonuria
Phenylketonuria is a rare genetic disorder characterized by the accumulation of phenylalanine in the blood, as the enzyme responsible for degrading phenylalanine has its function altered. Thus, the accumulation of phenylalanine, which can be found naturally in eggs and meat, for example, can become toxic for the child, potentially compromising neuronal development. See more about phenylketonuria.
How the treatment is carried out: The treatment of phenylketonuria consists of controlling and reducing the amount of this enzyme in the blood and, to this end, it is important that the child avoids consuming foods rich in phenylalanine, such as meat, eggs and oilseeds. As food can be quite restrictive, it is important that the child is monitored by a nutritionist to avoid nutritional deficiencies.
2. Congenital hypothyroidism
Congenital hypothyroidism is a situation in which the baby’s thyroid cannot produce normal and sufficient amounts of hormones, which can interfere with the baby’s development, as well as cause mental retardation, for example. Know how to identify the symptoms of congenital hypothyroidism.
How the treatment is carried out: Treatment for congenital hypothyroidism begins as soon as the diagnosis is made and consists of the use of medication to replace thyroid hormones that are in altered amounts, as this ensures the child’s healthy growth and development.
3. Sickle cell anemia
Sickle cell anemia is a genetic problem characterized by changes in the shape of red blood cells, reducing their ability to transport oxygen to various parts of the body, which can cause delays in the development of some organs.
How the treatment is carried out: Depending on the severity of the disease, the baby may need blood transfusions so that oxygen is transported to the organs correctly. However, treatment is only necessary when infections such as pneumonia or tonsillitis appear.
4. Congenital adrenal hyperplasia
Congenital adrenal hyperplasia is a disease that causes the child to have a hormonal deficiency of some hormones and an exaggerated production of others, which can cause excessive growth, precocious puberty or other physical problems.
How the treatment is carried out: In these cases, it is important to identify the altered hormones so that hormone replacement can be carried out, which in most cases needs to be carried out throughout life.
5. Cystic fibrosis
Cystic fibrosis is a problem in which a large amount of mucus is produced, compromising the respiratory system and also affecting the pancreas, which is why it is important that the disease is identified in the heel prick test so that treatment can be initiated and treatment can be complications prevented. Learn how to identify cystic fibrosis.
How the treatment is carried out: The treatment of cystic fibrosis involves the use of anti-inflammatory medicines, adequate nutrition and respiratory physiotherapy to alleviate the symptoms of the disease, especially difficulty breathing.
6. Biotinidase deficiency
Biotinidase deficiency is a congenital problem that causes the body’s inability to recycle biotin, which is a very important vitamin for ensuring the health of the nervous system. Therefore, babies with this problem may experience seizures, lack of motor coordination, developmental delays and hair loss.
How the treatment is carried out: In these cases, the doctor recommends taking the vitamin biotin for life to compensate for the body’s inability to use this vitamin.
Extended heel prick test
The expanded heel prick test is carried out with the aim of identifying other diseases that are not as common, but which can occur especially if the woman has had any changes or infections during pregnancy. Therefore, the expanded heel prick test can help identify:
- Hyperphenylalaninemia, which are changes related to excess phenylalanine in the blood, which can cause changes in behavior and cognitive development;
- Hemoglobinopathieswhich are diseases related to hemoglobin, which can compromise the transport of oxygen to the body;
- Congenital toxoplasmosis: disease that can be fatal or lead to blindness, jaundice which is yellowish skin, convulsions or mental retardation;
- Galactosemia: disease that causes the child to be unable to digest the sugar present in milk, which can lead to impairment of the central nervous system;
- Glucose-6-phosphate dehydrogenase deficiency: facilitates the appearance of anemia, which can vary in intensity;
- Aminoacidopatiaswhich are diseases related to the metabolism of amino acids, which can result in changes in the formation of proteins;
- Lysosomal diseaseswhich are diseases that interfere with the functioning of cells;
- Primary immunodeficiencieswhich correspond to genetic changes in the immune system, resulting in changes in the body’s response against infectious agents and combating diseases;
- Spinal muscular atrophywhich is a rare alteration in which there is a change in the nerve cells of the spinal cord, which can cause difficulty or absence of voluntary muscle movements;
- Congenital syphilis: a serious illness that can lead to impairment of the central nervous system;
- HIV infection: disease that leads to serious impairment of the immune system, which still has no cure;
- Congenital rubella: causes congenital deformities such as cataracts, deafness, mental retardation and even heart defects;
- Congenital herpes: rare disease that can cause localized lesions on the skin, mucous membranes and eyes, or disseminated, seriously affecting the central nervous system;
- Congenital cytomegalovirus disease: can generate cerebral calcifications and mental and motor retardation;
- Congenital Chagas disease: an infectious disease that can cause mental and psychomotor retardation and ocular changes.
The heel prick test expanded by the SUS should be available from May 2022, being carried out in stages established by the Ministry of Health.
