Newborn screening, commonly known as NBS, is a list of simple yet important tests given to newborn babies between24 – 72 hours of birth to screen for congenital metabolic disorders and conditions. Some of these conditions are not clinically evident until irreversible and permanent damage is already done. However, these simple screening tests done at the earliest manage to bring congenital conditions, metabolic disorders, and blood diseases to the fore which help doctors provide immediate and necessary treatment.
It should be noted that the newborn screening tests are not diagnostic tests; however, they successfully identify babies who may have certain life-threatening conditions that require immediate follow-up testing and treatment.
While these tests are mandatory and is conducted through Government funded screening centers in certain countries, it is still not compulsory in India.
The population of the Asia Pacific constitutes over half of the total world population and births in this region comprise 49% of annual births worldwide (9). However, NBS coverage in some of the developing countries in the Asia Pacific remains very low (< 1%).
When is NBS done?
Ideally NBS is done between 24 – 72 hours of birth. If the baby is born in a hospital, it is easy to request the medical staff for these tests. The staff will conduct the necessary tests, send the blood samples for testing and report to the hospital. The concerned doctor will inform you about the results and also let you know about the next course of action if there is any cause for concern. If the baby is born at home, it is important to take the baby to the nearest health center to get screening tests done. Although getting the tests within 72 hours is ideal; however, it should be done not later than 7th day after birth. In case, you leave the hospital within 24 hours after delivery, you should bring the baby back to the hospital for these tests.
According to World Health Organisation (WHO), 140 million children are born every year, of which 5 million children die in the first month of life in the developing countries and 4 million children are born with some genetic abnormality.
How is NBS done?
Newborn Screening tests are done using whole blood drawn from the heel of the babies and collected on a special filter paper. This is a very simple and fairly painless method of pricking the heel of the baby to draw a very small amount of blood. The blood drawn is then placed on a specially designed filter paper and sent to the screening lab. The paper also comes with a form that contains important information about the baby – such infant birth weight, gestational age, date and time of birth and of sample collection. The hearing test is conducted using a soft ear plug.
Although there is no hard and fast rule about the number of conditions to test for; however, the screening tests are usually conducted for 31 core disorder types. Your baby is generally tested for the following:
- Phenylketonuria – a metabolic disorder that increases amino acids in the body. It is observed that there is a high prevalence of inborn errors of metabolism (metabolic genetic disorders) to the extent of 1 in every thousand births in India.
- Congenital Hypothyroidism – An absence of thyroid hormone which if undetected affects physical and mental growth.A prevalence of congenital hypothyroidism 1 in 1700 , congenital adrenal hypothyroidism 1 in 2575 and aminoacid disorders 1 in 3600 was observed in India.
- Congenital Adrenal Hyperplasia – An endocrine system disorder which causes severe dehydration, salt loss, gene mutations and abnormal male sex hormones.
- Galactosemia – A condition which prevents babies from processing galactose. The increase in galactose causes brain and liver damage and also cataract.
- Sickle Cell Anemia – Anemia caused because of the abnormal functioning of the red blood cells which are not in the right shape.
- Cystic fibrosis – A condition that affects bowel movements, digestive system and also lung functioning.
- Hearing Test – Screening for hearing disability.
A newborn baby with a congenital metabolic disorder might appear completely normal; it becomes extremely important for NBS to be done so that treatment can be provided even before clinical symptoms become apparent. Newborn screening tests are conducted to identify the presence of rare and serious conditions in babies. Although these tests only provide preliminary information, they help pediatricians and doctors determine if more accurate diagnostic tests are further needed.