This test screens for disorders involving the metabolism of nutrients in the body, which lead to abnormalities in body chemistry. Our bodies need proteins, fats and carbohydrates to be broken down and absorbed from the foods that we eat so that we can build body tissues like muscle, bones, blood, nerves and brain tissue.
Enzymes are body chemicals that are involved in the process of breaking down the proteins, fats and carbohydrates into substances that the body can use. Most disorders of metabolism are due to a lack of a certain enzyme, leading to a problem with the breakdown of a certain nutrient. The body then cannot derive the benefit of this nutrient, which results in a disease or disorder of body chemistry.
In some disorders, there is a problem in the transport and usage of nutrients, which can also lead to the development of a disease or disorder in body chemistry.
Newborn screening tests are designed to pick up these diseases and disorders before any harmful effects set in. As most affected children show no sign of the disease at birth, the tests have to be done within 48 – 72 hours of birth.
Amino acids are the building blocks that make up proteins in our food. A number of different enzymes are needed to process these amino acids for our body to use. A problem with these enzymes means that the body cannot utilise the amino acids properly, and they can build up to dangerous levels in the body and cause damage to the brain, or liver or other organs.
These disorders also involve faulty enzymes in protein metabolism. The body cannot utilise the proteins properly resulting in a build-up of harmful substances that affect the organs of the body.
The body uses fat to create energy, which is essential for growth and normal development. The body’s process of breaking down fat is called “fatty acid oxidation” and involves a number of enzymes. Problems with these enzymes will cause fatty acid oxidation disorders, and affected children will not be able to breakdown fat from either food or their own body fat stores.
Milk, which is baby’s first food, contains a sugar called galactose. Disorders involving enzymes that breakdown galactose can cause a build up that is extremely toxic to the body.
Hormones are our body’s chemical messengers, sending messages from one place to another and regulating various processes in the body. Hormones are made by the endocrine glands such as the thyroid, the ovaries, the testes and the adrenal glands.
Cystic fibrosis (CF) is one of the most common inherited (from both parents) childhood diseases. It’s a disorder in which there is a problem in the regulation of movement of water and salt in and out of the body cells. The result is a body’s inability to properly secrete fluids like sweat, tears, digestive enzymes and mucus. The fluids become thick, and cause blockages in parts of the body like the respiratory tract, pancreas, intestine, liver, sweat glands and male genital tract.
Since we do not know which child may be at risk of a metabolic disease, international practice recommends that all children undergo newborn screening. By testing all children, we’re assured of finding the few that are affected, for whom early detection and treatment of the disease is vital.
When should newborns be screened?
The ideal time is between 48 and 72 hours after the birth, but up to a week after birth is still acceptable. The baby needs to have had a few feeds and started the digestion and metabolism of proteins, carbohydrates and fats (all found in breast milk and formula milk) to bring the disorder to light.
Tests done outside the ideal timeframe may still be useful, but they become less accurate.
Sometimes, the laboratory at North-West University will request that the test be repeated. It does not necessarily mean there is anything wrong with the baby – it may be that the sample was not collected properly, and not enough blood was available for testing. Repeat tests may be requested in as many as 10% of cases.
If something is found to be abnormal with the results, a repeat test, and sometimes additional blood and urine tests, may be required. Don’t be alarmed by the request for further testing, as it doesn’t mean that there’s definitely something wrong with the baby. Often, when the first test suggests a problem, the results cannot be considered final until a repeat test is done. This requires a new blood sample. The doctors at Next Biosciences and your paediatrician will discuss the need for further tests with you.
You will be notified of the result within 7 -10 working days of the test being done
If a test comes back positive for any of the disorders, your paediatrician will contact you immediately. Each disorder is treatable in its own way, even though they’re not curable. Your paediatrician will guide you through the explanation of the disease, and the ways in which it can be treated. Next Biosciences is also able to organise a genetic counsellor to counsel you about the implications of the disease.
In most instances, treatment consists of dietary modifications, dietary supplementation, hormones and sometimes medication. If your baby has one of these conditions, it is very important that treatment is started as soon as possible.
The baby will feel little discomfort during the heel prick and may cry a bit. The testing is not harmful at all.