Newborn Screening – Tests & Importance

Newborn Screening is a safe and simple test that screens over 50 metabolic and genetic conditions that can be hidden in your baby.

Screening for a disease should be done for those diseases which fulfill following criteria:

  • It should be an important health concern
  • Test should be simple to do and reliable
  • Disease should not manifest at birth
  • Treatment will prevent significant morbidity and mortality
  • Delay in diagnosis will cause irreversible damage
  • Screening has to be cost effective

Newborn screening for common metabolic disorders should be an integral part of newborn care as early detection and treatment can help prevent intellectual and physical defects and life threatening illnesses. It has been divided into 3 categories.

Category A is recommended for all newborns and the diseases include Congenital hypothyroidism, Hearing deficit, congenital adrenal hyperplasia, G-6-PD deficiency and sickle cell disease.

Category B is high risk screening: Screening for the following disorders should be conducted in the high risk population (consanguinity, previous children with unexplained intellectual disability, seizure disorder, previous unexplained sibling deaths, critically ill neonates, newborns/children with symptoms/ signs/investigations suggestive of inborn errors of metabolism). These conditions include phenylketonuria, homocystinuria, alkaptonuria, galactosemia, sickle cell anemia and other hemoglobinopathies, cystic fibrosis, biotinidase deficiency, maple syrup urine disease, medium-chain acyl-CoA dehydrogenase deficiency, tyrosinemia and fatty acid oxidation defects.

Category C involves screening (in resource-rich setting/expanded screening) for 30-40 inherited metabolic disorders may be offered to ‘well-to-do’ families, especially in urban settings where facilities for sending sample to laboratory are available.

The conditions for which neonatal screening has been proposed in Indian scenario include hearing loss, congenital hypothyroidism, congenital adrenal hyperplasia (CAH) and glucose-6-phosphate dehydrogenase (G6PD) deficiency.

  • Hearing loss has a high incidence, and if not corrected before 6 months of age, may lead to permanent hearing and speech impairment.
  • Congenital hypothyroidism also has a incidence of 1 in 1700 babies and is the most important preventable cause of intellectual disability. A lack or absence of thyroid hormone, which is necessary for growth of the brain and the body. Treatment is required within the first few days to prevent problems in physical and mental growth (IQ).
  • Congenital adrenal hyperplasia has an incidence of 1 in 2750 cases. If undetected at birth, can result in mortality, morbidity or genital abnormalities. An endocrine disorder that causes severe salt loss, dehydration, and abnormally high levels of male sex hormones. Left undetected and untreated, a baby may die within seven to 14 days.
  • G6PD deficiency has a relatively high incidence in Northern parts of the country. A condition where the body lacks the enzyme called G6PD deficiency of which may cause haemolytic anaemia (which means the body doesn’t have enough healthy red blood cells), resulting from exposure to oxidative substances present in certain drugs and foods esp fava beans.
  • Cystic fibrosis is a condition that affects the way lungs and gastro intestinal system work. This makes it difficult for baby’s body to digest food properly, which means he doesn’t get enough nutrients. This can cause problems with digestion and bowel movements, and may also lead to diabetes.
  • Sickle cell anaemia – the incidence of which is 1 in 5100 babies which results in anaemia because the red blood cells are not the right shape and so cannot work the way they are meant to resulting in severe painful crisis and increased propensity to cause infections.

Why do babies require blood tests?

We are aware of the fact that most of the kids look healthy and are healthy at birth. Once feeding is initiated there are certain metabolites which get formed as a consequence of digestion of milk which can result into production of harmful substances which doesn’t allow child to grow well. If detected on time and treated appropriately the damage to the child is prevented.

What is the data as far as India is concerned?

In India, only less than 1% of infants are screened and every year over 1.6 million babies are born with birth defects. The mortality rate in India is at an alarming 44 per thousand live births.

It is important to remember that a baby might appear completely normal at birth, but it is still important to do this test.  As most of these conditions are hidden and are not apparent at birth. It is also good to get the test done early as this can pave way to get timely treatment and save the child from several irreversible damages.

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