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Screening Tests for Newborns

By

Deborah M. Consolini

, MD, Thomas Jefferson University Hospital

Last full review/revision Sep 2021| Content last modified Sep 2021
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Screening recommendations for newborns vary by clinical context and state requirements.

Blood typing is indicated when the mother has type O or Rh-negative blood or when minor blood antigens are present because hemolytic disease of the newborn is a risk.

All neonates are evaluated for jaundice throughout the hospital stay and before discharge . The risk of hyperbilirubinemia Neonatal Hyperbilirubinemia Jaundice is a yellow discoloration of the skin and eyes caused by hyperbilirubinemia (elevated serum bilirubin concentration). The serum bilirubin level required to cause jaundice varies with... read more is assessed using risk criteria, measurement of bilirubin, or both. Bilirubin can be measured transcutaneously or in serum. Many hospitals screen all neonates and use a predictive nomogram to determine the risk of extreme hyperbilirubinemia. Follow-up is based on age at discharge, predischarge bilirubin level and/or rate of bilirubin rise from one determination to another, and risk of developing jaundice.

Most states test for specific inherited diseases Introduction to Inherited Disorders of Metabolism Most inherited disorders of metabolism (also called inborn errors of metabolism) are caused by mutations in genes that code for enzymes; enzyme deficiency or inactivity leads to Accumulation... read more , including phenylketonuria Phenylketonuria (PKU) Phenylketonuria is a disorder of amino acid metabolism that causes a clinical syndrome of intellectual disability with cognitive and behavioral abnormalities caused by elevated serum phenylalanine... read more , tyrosinemia Tyrosine Metabolism Disorders Tyrosine is an amino acid that is a precursor of several neurotransmitters (eg, dopamine, norepinephrine, epinephrine), hormones (eg, thyroxine), and melanin; deficiencies of enzymes involved... read more , biotinidase deficiency, homocystinuria Classic homocystinuria A number of defects in methionine metabolism lead to accumulation of homocysteine (and its dimer, homocystine) with adverse effects including thrombotic tendency, lens dislocation, and central... read more , maple syrup urine disease Maple syrup urine disease Valine, leucine, and isoleucine are branched-chain amino acids; deficiency of enzymes involved in their metabolism leads to accumulation of organic acids with severe metabolic acidosis. There... read more , galactosemia Galactosemia Galactosemia is a carbohydrate metabolism disorder caused by inherited deficiencies in enzymes that convert galactose to glucose. Symptoms and signs include hepatic and renal dysfunction, cognitive... read more , congenital adrenal hyperplasia Overview of Congenital Adrenal Hyperplasia Congenital adrenal hyperplasia is a group of genetic disorders, each characterized by inadequate synthesis of cortisol, aldosterone, or both. In the most common forms, accumulated hormone precursors... read more , sickle cell disease Sickle Cell Disease Sickle cell disease (a hemoglobinopathy) causes a chronic hemolytic anemia occurring almost exclusively in blacks. It is caused by homozygous inheritance of genes for hemoglobin (Hb) S. Sickle-shaped... read more Sickle Cell Disease , and hypothyroidism Hypothyroidism in Infants and Children Hypothyroidism is thyroid hormone deficiency. Symptoms in infants include poor feeding and growth failure; symptoms in older children and adolescents are similar to those of adults but also... read more . Some states also include testing for cystic fibrosis Cystic Fibrosis Cystic fibrosis is an inherited disease of the exocrine glands affecting primarily the gastrointestinal and respiratory systems. It leads to chronic lung disease, exocrine pancreatic insufficiency... read more Cystic Fibrosis , disorders of fatty acid oxidation Overview of Fatty Acid and Glycerol Metabolism Disorders Fatty acids are the preferred energy source for the heart and an important energy source for skeletal muscle during prolonged exertion. Also, during fasting, the bulk of the body’s energy needs... read more , other organic acidemias, and severe combined immunodeficiency Severe Combined Immunodeficiency (SCID) Severe combined immunodeficiency is characterized by low to absent T cells and a low, high, or normal number of B cells and natural killer cells. Most infants develop opportunistic infections... read more .

HIV screening is required by some states and is indicated for children of mothers known to be HIV-positive or those engaging in HIV high-risk behaviors.

Screening for critical congenital heart disease (CCHD) using pulse oximetry is part of routine newborn assessment. Previously, newborns were screened for CCHD by prenatal ultrasonography and by physical examination, but this approach failed to identify many cases of CCHD, which led to increased morbidity and mortality. The screening is done when infants are ≥ 24 hours old and is considered positive if

  • Any oxygen saturation measurement is < 90%.

  • The oxygen saturation measurements in both the right hand and foot are < 95% on 3 separate measurements taken 1 hour apart.

  • There is > 3% absolute difference between the oxygen saturation in the right hand (preductal) and foot (postductal) on 3 separate measurements taken 1 hour apart.

Any infant with a positive screen should have additional testing, including chest x-ray, electrocardiography, and echocardiography. The infant’s pediatrician should be notified, and the infant may need to be evaluated by a cardiologist.

Hearing screening varies by state. Hearing loss Hearing Impairment in Children Common causes of hearing loss are genetic defects in neonates and ear infections and cerumen in children. Many cases are detected by screening, but hearing loss should be suspected if children... read more Hearing Impairment in Children is one of the most frequently occurring birth defects. About 3/1000 infants are born with moderate, profound, or severe hearing loss. Hearing loss is even more common among infants admitted to an intensive care unit at birth. Currently, some states screen only high-risk neonates (see Table: High-Risk Factors for Hearing Deficits in Neonates High-Risk Factors for Hearing Deficits in Neonates Screening recommendations for newborns vary by clinical context and state requirements. Blood typing is indicated when the mother has type O or Rh-negative blood or when minor blood antigens... read more ); others screen all neonates. Initial screening often involves using a handheld device to test for echoes produced by healthy ears in response to soft clicks (otoacoustic emissions); if this test is abnormal, auditory brain stem response (ABR) testing is done. Some institutions use ABR testing as an initial screening test. Further testing by an audiologist may be needed.

Table

High-Risk Factors for Hearing Deficits in Neonates

Factor

Specifics

Birth weight

< 1500 g

Apgar score

7 at 5 minutes

Serum bilirubin

> 22 mg/dL (> 376 micromol/L) in neonate whose birth weight is > 2000 g

> 17 mg/dL (> 290 micromol/L) in neonate whose birth weight is < 2000 g

Disorders

Perinatal anoxia or hypoxia

Congenital infections

Maternal exposure

Aminoglycosides

Family history

Early hearing loss in a parent or close relative

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