A screening test is a test that aims to detect any potential health problems or diseases in someone who doesn’t have any signs or symptoms of the disease. Many diseases can be treated much more effectively if they are diagnosed early on. When your baby is born, a full physical check will be done by a midwife or doctor with the aim of recognising any obvious abnormalities. However, there are many conditions and abnormalities that we cannot see from the outside, but that can be identified through newborn screening tests.
South Africa is woefully behind when it comes to screening newborns. Tests that are done routinely in many other countries are not part of our routine healthcare programme. They are available, but they are often not recommended by the doctors and midwives who care for mothers. Many of these professionals are still under the impression that some conditions are so rare that we don’t really need to worry about it. The actual statistics tell a different story.
Are newborn screening tests accurate?
These newborn screening tests show us babies who are at a bigger risk of having a condition. Further tests would need to be done to confirm a diagnosis. Very often the follow-up (diagnostic) tests may show no abnormalities at all. For this reason one should not panic if an initial screening test is positive.
What are the costs of newborn screening?
This will depend on the newborn screening tests done and laboratory that does it. Screening carries some expense, and while the medical aid pays for some of the tests, there may still be some cost to the parents. This may well be the reason why many parents choose not to do a screening. Remember that any follow-up tests will also cost money.
Of course for the baby with whom there was nothing wrong, this money was technically wasted. But for the little one who had a condition, early diagnosis makes a difference beyond measure.
In this blog, we would like to introduce the three most common newborn screening tests
- Screening for metabolic diseases in newborns
- Newborn hearing screening
- TSH screening
Screening for genetic metabolic diseases
Of the above-mentioned screening tests, this one is most important to read about as it is the test most neglected in South Africa. In fact, less than 1% of babies are screened for metabolic disease at birth!
Metabolic screening at birth is part of routine care in all developed and many developing countries. In Egypt more than 95% of babies are screened, and in Iran more than 85%.
But what are metabolic diseases? In most cases a metabolic disease leads to the body not being able to break down or to use a certain component of food. This causes a toxic build-up of this substance in the brain and liver, and other tissues. With some of these diseases babies are killed by their condition in the early weeks of life, while others develop permanent disabilities. In others it may take 2-3 years before symptoms start showing and a diagnosis is made.
There are hundreds of genetic metabolic diseases known to us, and new ones are still being discovered.
If an early diagnosis is made most of these conditions can be treated effectively, and any long term harm can successfully be prevented. A child that would otherwise have gotten brain damage or even died, will be able to live a normal life.
Most healthcare practitioners do not recommend screening, as they feel that the incidence of these diseases is so low that it does not justify the cost of screening. This is simply not true. In South Africa it is estimated that between 1 in 1000 and 1 in 2000 babies born with a genetic metabolic disease. Some of these diseases are even more prevalent in certain population groups in our country than in the rest of the world.
To put it in perspective, 1 in 500 babies are born with Down’s Syndrome, and 1 in 2000 children will develop Leukaemia. Yet these conditions are not seen as exceptionally rare.
The good news is that the cost of screening has really decreased in recent years, as technology has become more advanced. If a positive screen needs to be repeated it is usually done free of charge. If further tests are necessary to confirm a diagnosis it will become more expensive. But this cost will still pale in comparison to the millions that an untreated disease or disability is going to cost over a child’s lifespan.
The screening is done via a heel prick, and needs to be done within 24-72 hours after birth. If you want to have this screening done you need to arrange it beforehand with your gynaecologist, midwife or paediatrician. Know that it is probably not going to be routinely offered. You can visit www.nextbio.co.za for more information.
Newborn hearing screening
In South Africa between 4 and 6 children out of every 1000 live births suffer from hearing loss, making it one of the most common disabilities. Children can also contract hearing loss in the first 2 years of life in response to for example ear infections, or other viral infections.
All babies should be screened for hearing loss at birth, and again at 1 year and at 2 years of age. In recent years the awareness around this has grown, but in South Africa, most babies are still not screened at birth and almost no babies after that.
On average hearing loss is only diagnosed after two years of age. By this time, it has had a massive impact on baby’s speech and language development, and on their social development.
Parents think that they will know if their children are unable to hear. But this is mostly not the case. A child may have enough hearing to respond to loud sounds, but may not be able to hear the softer sounds that they need in order to develop language and speech. Often hearing tests are only done when parents note a delay in baby’s speech development. By then a lot of harm has been done.
The most common method used to measure baby’s hearing is called Otoacoustic Emissions (OAE). A tiny probe is placed just inside baby’s ear canal. It plays a click and then measures the response (echo) that comes back from the inner ear. This test is painless and can be done while baby is sleeping. If done in the first day or two after birth there may still be some amniotic fluid in baby’s ears, which can affect the test. For this reason, a positive test will be repeated before any further referral is done.
TSH stands for thyroid-stimulating hormone, a hormone that does at it says, which is to stimulate the thyroid gland to work.
After baby is born blood is collected from the cord and sent away to test baby’s TSH levels. If these levels are high, it may mean that baby’s thyroid gland is not working. This is called congenital hypothyroidism and means that either baby was born without a thyroid gland, or that baby’s thyroid is unable to manufacture the hormones that it should.
At birth, a baby with congenital hypothyroidism will have no symptoms. But within the first few weeks to months after birth, symptoms will start developing and brain damage will occur. By the time that it is noted, baby’s growth and his development will be irreversibly affected.
If baby’s TSH levels are high at birth, bloods will be drawn to check the thyroid levels, and baby will be referred to a specialist if a problem is suspected. If congenital hypothyroidism is diagnosed baby will be put on medication that replaces the thyroid hormones. Although he will need to use this medication for the rest of his life, he will suffer no further negative effects of his condition.
This is incredibly sad, as many children are suffering a disability that could have been successfully prevented by a very simple and fairly affordable screening test. TSH screening is done in most private hospitals in South Africa, but not yet in government hospitals.