What Is Neonatal Screening?
Neonatal screening involves the tests done on the newborn baby to check for disorders with no apparent symptoms. Newborns will have the chance of having metabolic, hormonal, or genetic disorders. The parents will be offered such tests for their babies to screen for specific rare diseases that could be easily treated if diagnosed early. The neonatal screening test will be done 48 to 72 hours after birth. The neonatal screening tests are done in three parts: blood tests, neonatal hearing tests, and newborn heart screening.
What Is Neonatal Blood Test?
Severe disorders in newborns can be diagnosed with the help of neonatal blood tests. The test is also called the heel prick test. The doctor or the nurse will prick the baby's heel to collect a few blood drops, which will be sent to the laboratory for testing. The heel prick test will be received within five to seven days. The test is also called a blood spot test, as the blood spots will be collected on a card for further testing. This test is used to screen the following conditions:
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Sickle Cell Anemia: A group of disorders called sickle cell disease constitute sickle cell anemia. It is an inherited group of conditions affecting the red blood cell or RBC shape. This impairs the oxygen-carrying function of the cells.
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Severe Combined Immunodeficiency: A group of conditions and primary immunodeficiency diseases are included in severe combined immunodeficiency. It may progress to life-threatening immune problems in the individual.
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Cystic Fibrosis: Cystic fibrosis affects the digestive system, lungs, and other organs. It is an inherited life-threatening condition.
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Congenital Hypothyroidism: Congenital hypothyroidism is the deficiency of thyroid hormones at birth. If not treated at the appropriate time, it may lead to irreversible conditions involving neurological deficits.
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Inborn Errors of Metabolism: Inherited metabolic diseases or inborn errors of metabolism are genetic or heritable disorders. It includes conditions like phenylketonuria, albinism, and cystinuria.
How Is Neonatal Hearing Test Done?
The neonatal hearing test is called the automated otoacoustic emission (AOAE) test. It takes just a few minutes for the test. The healthcare provider will place a soft earpiece in the baby's ear. A clicking sound will be played. There are chances that the test may produce faulty results on the first attempt, but that does not mean that the baby is having hearing difficulties. Incorrect results can be due to the following reasons:
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Baby might be unsettled while doing the test.
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The baby might have a blocked ear due to fluid accumulation.
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There might be loud noises in the background while doing the test.
In such a case, the baby will be subjected to a second round of neonatal hearing screening, and the same procedure will be repeated.
Another neonatal hearing test type is the automated auditory brainstem response (AABR) test. AABR test may take five to fifteen minutes. Three sensors will be used for the examination and placed on the baby’s neck and head. The soft headphones will be placed on the baby’s ears, and a gently clicking sound will be played.
What Is Neonatal Heart Screening?
Congenital heart disease in the fetus can be diagnosed with the help of maternal genetic testing in the form of ultrasound scanning, like a fetal echocardiogram. However, certain heart defects remain undiagnosed in the fetal stage and can be screened with the help of neonatal heart screening. A pulse oximetry test will be conducted for neonatal heart screening. Pulse oximetry estimates the level of oxygen in the blood of the newborn, a low level of which is a sign of a critical congenital heart defect. It uses a pulse oximeter, whose sensors will be placed on the baby.
What Happens if the Neonatal Screening Results Are Abnormal?
In most cases, the results of neonatal screening tests will not be normal. An abnormal test result does not always mean the newborn has a severe disorder. It may be due to faulty procedures, unexpected atmosphere, or the restless nature of the newborn. In case of abnormal results for the neonatal screening tests, the newborn will be subjected to more testing. Further tests will be a diagnostic tool that helps confirm whether the baby has an underlying condition. If the results of the diagnostic tests are normal, the baby will not have any disorder. In other cases, the newborn will be subjected to treatments and management steps respective to the diagnosed conditions.
What Are the Benefits of Neonatal Screening Test?
Neonatal screening tests are done to screen the following health conditions in the newborn:
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Organic Acid Metabolism Disorders: This includes propionic acidemia or PROP (deficiency of propionyl-CoA carboxylase), methylmalonic acidemia (a condition where protein and fat breakdown gets affected), glutaric acidemia (abnormal organic acid buildup), and others.
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Endocrine Disorders: These include congenital adrenal hyperplasia (a congenital condition where the adrenal glands produce a limited amount of hormone) and primary congenital hypothyroidism.
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Fatty Acid Oxidation Disorders: This includes carnitine uptake or transport defect, medium-chain acyl-CoA dehydrogenase deficiency (an inherited condition affecting fat breakdown), very long-chain acyl-CoA dehydrogenase deficiency (a disorder where conversion of fat to energy gets affected), and others.
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Hemoglobin Disorders: This includes sickle cell anemia, beta thalassemia (presence of less hemoglobin in the blood), and sickle cell disease.
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Amino Acid Metabolism Disorders: This includes argininosuccinic aciduria (a condition where ammonia gets accumulated in the blood), maple syrup urine disease (a condition where the body finds it difficult to process certain amino acids), homocystinuria (inability to process methionine) and others.
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Other Disorders: Neonatal screening also screens for disorders like critical congenital heart disease, biotinidase deficiency, hearing loss, classic galactosemia, cystic fibrosis, and others.
Conclusion
Neonatal screening tests are aids that help screen the newborn for many disorders present by birth. These tests may be done in the first one to two days of their life. It helps screen the diseases as soon as possible and helps start the treatments as fast as possible. If left untreated, these conditions may progress to severe life-threatening problems. Newborn screening tests are done in three parts: blood test, newborn heart screening test, and neonatal hearing tests. Further diagnostic tests may be done for confirmation in case of an abnormal test result.
