Newborn Screening Extended (Expanded Newborn Screening)

Expanded Newborn Screening Test

It is a blood test done in newborn babies to screen for certain rare diseases and disorders which may have serious consequences if not detected and treated promptly. This test is also called extended new born screening test.

This test is done usually within 24 to 48 hours of birth of the baby. It helps in screening for certain inherited conditions which may lead to serious problems in baby later on during infancy and childhood. This test helps to diagnose those particular diseases which may be life threatening or may hamper physical and mental development of the child.

Since it is a screening test, it helps to identify those babies which may have a particular disorder so that confirmatory tests can be done for early diagnosis. Hence timely medical intervention can be done to reduce the morbidity and mortality associated with those disorders.

The various diseases screened with the help of this test are genetic, hormonal and metabolic.

The metabolic diseases screened are also called inborn error of metabolism(IEM).IEM are those disorders which occur due to abnormal accumulation of certain chemicals in the body due to deficiency or inappropriate functioning of certain enzymes . It may have various manifestations like delayed physical and mental development, brain damage and even death. But if diagnosed and treated promptly, these children can have normal healthy life.

What are the components of expanded newborn screening test?

This test includes screening for metabolic disorders such as:

• Phenylketonuria
• Methylmalonic academia
• Maple syrup urine disease
• Tyrosinemia
• Citrullinemia
• Medium chain acyl CoA dehydrogenase (MCAD)deficiency
• homocystinuria

This test includes screening for hormonal disorders such as:

• Congenital hypothyroidism
• Congenital adrenal hyperplasia

This test includes screening for haemoglobin disorders such as:

• Sickle cell disease
• Beta thalassemia
• Haemoglobin SC disease

Other rare disorders screened are:

• Galactosemia
• Biotidinase deficiency
• Cystic fibrosis
• Severe combined immunodeficiency(SCID)
• Pompe disease
• Spinal muscle atrophy
• Mucopolysaccharidosis type 1

This test included screening for 30 such rare disorders.

Procedure and prerequisites

This test is done on blood which is collected by pricking heel of the newborn baby. Only one full drop of blood is put on 3 spots of filter paper provided from the laboratory. After the paper dries out it has to be sent to the lab for the test. The procedure used for this test is called tandem mass spectrometry. Detailed clinical history and drug history must be included. No specific risk of bleeding or infection is there while taking the sample.

These all should be submitted along with test requisition form. Appropriate further testing is done on the received specimens to come at an optimal conclusion/diagnosis

Reference range

The result of expanded newborn screening test can be either positive or negative.