NBS


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NBS

Abbrevation for:
National Blood Service (Medspeak-UK)
National Board For Nursing, Midwifery & Health Visiting For Scotland (obsolete) (Medspeak-UK)
National Bureau of Standards (USA) (now, National Institute of Standards & Technology)
neonatal Bartter syndrome
newborn screening
no bacteria seen
normal bowel sounds
normal brain stem
normal breath sounds
nystagmus blockage syndrome

NBS

Newborn screening, see there.

Newborn Screening

Synonym/acronym: NBS, newborn metabolic screening, tests for inborn errors of metabolism.

Common use

To evaluate newborns for congenital abnormalities, which may include hearing loss; identification of hemoglobin variants such as thalassemias and sickle cell anemia; presence of antibodies that would indicate a HIV infection; or metabolic disorders such as homocystinuria, maple syrup urine disease (MSUD), phenylketonuria (PKU), tyrosinuria, and unexplained mental retardation.

Area of application

Ears for hearing tests.

Specimen

Whole blood for metabolic tests.

Normal findings

(Method: Thyroxine, TSH, and HIV—immunoassay; amino acids—tandem mass spectrometry; hemoglobin variants—electrophoresis)
Hearing Test
AgeNormal Findings
Neonates–3 daysNormal pure tone average of −10 to 15 dB
Thyroid-Stimulating Hormone (TSH)
AgeConventional UnitsSI Units (Conventional Units × 1)
Neonates–3 daysLess than 20 micro-international units/mLLess than 20 milli-international units/L
Thyroxine, Total
AgeConventional UnitsSI Units (Conventional Units × 17.1)
Neonates–30 days5.4–22.6 mcg/dL92–386 nmol/L
HemoglobinopathiesNormal Hemoglobin Pattern
Blood spot amino acid analysisNormal findings. Numerous amino acids are evaluated by blood spot testing, and values vary by method and laboratory. The testing laboratory should be consulted for corresponding reference ranges.
HIV antibodiesNegative

Description

Newborn screening is a process used to evaluate infants for disorders that are treatable but difficult to identify by direct observation of diagnosable symptoms. The testing is conducted shortly after birth and is mandated in all 50 states and U.S. territories through a collaborative effort between government agencies, local public health departments, hospitals, and parents. Testing is categorized as core tests and second-tier tests. The testing included in mandatory newborn screening programs varies among states and territories; testing of interest that is not included in the mandatory list can be requested by a health-care provider (HCP), as appropriate. Confirmatory testing is performed if abnormal findings are produced by screening methods. Properly collected blood spot cards contain sufficient sample to perform both screening and confirmatory testing. Confirmatory testing varies depending on the initial screen and can include fatty acid oxidation probe tests on skin samples, enzyme uptake testing of skin or muscle tissue samples, enzyme assays of blood samples, DNA testing, gas chromatography/mass spectrometry, and tandem mass spectrometry. Testing for common genetically transferred conditions can be performed on either or both prospective parents by blood tests, skin tests, or DNA testing. DNA testing can also be performed on the fetus, in utero, through the collection of fetal cells by amniocentesis or chorionic villus sampling. Counseling and written, informed consent are recommended and sometimes required before genetic testing.

Every state and U.S. territory has a newborn screening program, which includes early hearing loss detection and intervention (EHDI). The goal of EHDI is to assure that permanent hearing loss is identified before 3 months of age, appropriate and timely intervention services are provided before 6 months of age, families of infants with hearing loss receive culturally competent support, and tracking and data management systems for newborn hearing screens are linked with other relevant public health information systems. For more detailed information refer to the monograph titled “Audiometry Hearing Loss”.

The adrenal glands are responsible for production of the hormones cortisol, aldosterone, and male sex androgens. Most infants born with congenital adrenal hyperplasia (CAH) make too much of the androgen hormones and not enough cortisol or aldosterone. The complex feedback loops in the body call for the adrenal glands to increase production of cortisol and aldosterone, and as the adrenal glands work harder to increase production, they increase in size, resulting in hyperplasia. CAH is a group of conditions. Most frequently, lack of or dysfunction of an enzyme called 21-hydroxylase results in one of two types of CAH. The first is a salt-wasting condition in which insufficient levels of aldosterone causes too much salt and water to be lost in the urine. Newborns with this condition are poor feeders and appear lethargic or sleepy. Other symptoms include vomiting, diarrhea, and dehydration, which can lead to weight loss, low blood pressure, and decreased electrolytes. If untreated, these symptoms can result in metabolic acidosis and shock, which in CAH infants is called an adrenal crisis. Signs of an adrenal crisis include confusion, irritability, tachycardia, and coma. The second most common type of CAH is a condition in which having too much of the androgen hormones in the blood causes female babies to develop masculinized or virilized genitals. High levels of androgens leads to precocious sexual development, well before the normal age of puberty, in both boys and girls.

Inadequate production of the thyroid hormone thyroxine can result in congenital hypothyroidism, which when untreated manifests in severely delayed physical and mental development. Inadequate production may be due to a defect such as a missing, misplaced, or malfunctioning thyroid gland. Inadequate production may also be due to the mother’s thyroid condition or treatment during pregnancy or, less commonly encountered in developed nations, a maternal deficiency of iodine. Most newborns do not exhibit signs and symptoms of thyroxine deficiency during the first few weeks of life while they function on the hormone provided by their mother. As the maternal thyroxine is metabolized, some of the symptoms that ensue include coarse, swollen facial features; wide, short hands; respiratory problems; a hoarse-sounding cry; poor weight gain and small stature; delayed occurrence of developmental milestones such as sitting up, crawling, walking, and talking; goiter; anemia; bradycardia; myxedema (accumulation of fluid under the skin); and hearing loss. Children who remain untreated usually become mentally retarded and demonstrate physical disabilities; they may have an unsteady gait and lack coordination. Most demonstrate delays in development of speech, and some have behavioral problems.

Hemoglobin (Hgb) A is the main form of Hgb in the healthy adult. Hgb F is the main form of Hgb in the fetus, the remainder being composed of Hgb A1 and A2. Hgb S and C result from abnormal amino acid substitutions during the formation of Hgb and are inherited hemoglobinopathies. Hgb S results from an amino acid substitution during Hgb synthesis whereby valine replaces glutamic acid. Hemoglobin C Harlem results from the substitution of lysine for glutamic acid. Hgb electrophoresis is a separation process used to identify normal and abnormal forms of Hgb. Electrophoresis and high-performance liquid chromatography as well as molecular genetics testing for mutations can also be used to identify abnormal forms of Hgb. Individuals with sickle cell disease have chronic anemia because the abnormal Hgb is unable to carry oxygen. The red blood cells of affected individuals are also abnormal in shape, resembling a crescent or sickle rather than the normal disk shape. This abnormality, combined with cell-wall rigidity, prevents the cells from passing through smaller blood vessels. Blockages in blood vessels result in hypoxia, damage, and pain. Individuals with the sickle cell trait do not have the clinical manifestations of the disease but may pass the disease on to children if the other parent has the trait (or the disease) as well.

Amino acids are required for the production of proteins, enzymes, coenzymes, hormones, nucleic acids used to form DNA, pigments such as hemoglobin, and neurotransmitters. Testing for specific aminoacidopathies is generally performed on infants after an initial screening test with abnormal results. Certain congenital enzyme deficiencies interfere with normal amino acid metabolism and cause excessive accumulation of or deficiencies in amino acid levels. The major genetic disorders include phenylketonuria (PKU), maple syrup urine disease (MSUD), and tyrosinuria. Enzyme disorders can also result in conditions of dysfunctional fatty acid or organic acid metabolism in which toxic substances accumulate in the body and, if untreated, can result in death. Infants with these conditions often appear normal and healthy at birth. Symptoms can appear soon after feeding begins or not until the first months of life, depending on the specific condition. Most of the signs and symptoms of amino acid disorders in infants include poor feeding, lethargy, vomiting, and irritability. Newborns with MSUD produce urine that smells like maple syrup or burned sugar. Accumulation of ammonia, a by-product of protein metabolism, and the corresponding amino acids, results in progressive liver damage, hepatomegaly, jaundice, and tendency to bruise and bleed. If untreated, there may be delays in growth, lack of coordination, permanent learning disabilities, and mental retardation. Early diagnosis and treatment of certain aminoacidopathies can prevent mental retardation, reduced growth rates, and various unexplained symptoms.

Cystic fibrosis (CF) is a genetic disease that affects normal functioning of the exocrine glands, causing them to excrete large amounts of electrolytes. CF is characterized by abnormal exocrine secretions within the lungs, pancreas, small intestine, bile ducts, and skin. Some of the signs and symptoms that may be demonstrated by the newborn with CF include failure to thrive, salty sweat, chronic respiratory problems (constant coughing or wheezing, thick mucus, recurrent lung and sinus infections, nasal polyps), and chronic gastrointestinal problems (diarrhea, constipation, pain, gas, and greasy, malodorous stools that are bulky and pale colored). Patients with CF have sweat electrolyte levels two to five times normal. Sweat test values, with family history and signs and symptoms, are required to establish a diagnosis of CF. Clinical presentation may include chronic problems of the gastrointestinal and/or respiratory system. CF is more common in Caucasians than in other populations. Testing of stool samples for decreased trypsin activity has been used as a screen for CF in infants and children, but this is a much less reliable method than the sweat test. Sweat conductivity is a screening method that estimates chloride levels. Sweat conductivity values greater than or equal to 50 mEq/L should be referred for quantitative analysis of sweat chloride. The sweat electrolyte test is still considered the gold standard diagnostic for CF.

Biotin is an important water-soluble vitamin/cofactor that aids in the metabolism of fats, carbohydrates, and proteins. A congenital enzyme deficiency of biotinidase prevents biotin released during normal cellular turnover or via digested dietary proteins from being properly recycled and absorbed, resulting in biotin deficiency. Signs and symptoms of biotin deficiency appear within the first few months and can result in hypotonia, poor coordination, respiratory problems, delays in development, seizures, behavioral disorders, and learning disabilities. Untreated, the deficiency can lead to loss of vision and hearing, ataxia, skin rashes, and hair loss.

Lactose, the main sugar in milk and milk products, is composed of galactose and glucose. Galactosemia occurs when there is a deficiency of the enzyme galactose-1-phosphate uridyl transferase, which is responsible for the conversion of galactose into glucose. The inability of dietary galactose and lactose to be metabolized results in the accumulation of galactose-1-phosphate, which causes damage to the liver, central nervous system, and other body systems. Newborns with galactosemia usually have diarrhea and vomiting within a few days of drinking milk or formula containing lactose. Other early symptoms include poor suckling and feeding, failure to gain weight or grow in length, lethargy, and irritability. The accumulation of galactose-1-phosphate and ammonia is damaging to the liver, and symptoms likely to follow if untreated include hypoglycemia, seizures, coma, hepatomegaly, jaundice, bleeding, shock, and life-threatening bacteremia or septicemia. Early cataracts can occur in about 10% of children with galactosemia. Most untreated children eventually die of liver failure.

HIV is the etiological agent of AIDS and is transmitted through bodily secretions, especially by blood or sexual contact. The virus preferentially binds to the T4 helper lymphocytes and replicates within the cells. Current assays detect several viral proteins. Positive results should be confirmed by Western blot assay. This test is routinely recommended as part of a prenatal work-up and is required for evaluating donated blood units before release for transfusion. The Centers for Disease Control and Prevention (CDC) has structured its recommendations to increase identification of HIV-infected patients as early as possible; early identification increases treatment options, increases frequency of successful treatment, and can decrease further spread of disease.

Core Conditions Evaluated in Many States
ConditionAffected ComponentMarker for DiseaseIncidencePotential Therapeutic InterventionsOutcomes of Therapeutic Interventions
Hearing lossDamage to or malformations of the inner earAbnormal audiogram1 in 3,000 birthsSurgery, medications for infections, removal of substances blocking the ear canal, hearing aidsA shorter period of auditory deprivation has a positive impact on normal development.
Congenital adrenal hyperplasia (CAH) (classical)Multiple types of CAH; majority have a deficiency of or nonfunctioning enzyme: 21-hydroxylase17-hydroxyprogesterone (17-OHP)1 in 25,000 births (75% have salt-wasting type; 25% have virilization type)Oral cortisone administration, surgery for females with virilizationPatients who begin treatment soon after birth usually have normal growth and development.
Congenital hypothyroidismMissing, misplaced, or malfunctioning thyroid gland resulting in insufficient thyroxine; insufficient thyroxine due to maternal thyroid condition or treatment with antithyroid medications during pregnancyThyroxine (total), thyroid-stimulating hormone1 in 5,000 birthsAdministration of L-thyroxinePatients who begin treatment soon after birth usually have normal growth and development.
HemoglobinopathiesVariant hemoglobinHgb S: amino acid substitution of valine for glutamic acid in the beta-globin chain; Hgb C: amino acid substitution of lysine for glutamic acid in the beta-globin chain; thalassemia: loss of 2 amino acids in the alpha-globin chain or decreased production of the beta-globin chainHgb S: 1 in 5,000 births, 1 in 400 births for African Americans; Hgb S/C: 1 in 25,000 births; Hgb S/beta-thalassemia 1 in 50,000 birthsCare of patients with Hgb S is complex, and the main goal is to prevent complications from infection, blindness from damaged blood vessels in the eye, anemia, dehydration, and fatigue. Some thalassemias may require iron supplementation.The goal with treatment is to lessen symptoms. Treatment cannot cure the condition. Symptoms may occur in spite of good treatment.
Inborn errors of amino acid metabolism
• ArgininemiaDeficiency of or non-functioning enzyme: arginaseArginineLess than 1 in 100,000 birthsConsultation with a dietician; low-protein diet supplemented by special medical foods and formulaPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Early treatment can help prevent high arginine and ammonia levels. Accumulation of these substances can cause brain damage, resulting in lifelong learning problems, mental retardation, or lack of coordination.
• Citrullinemia type IDeficiency of or non-functioning enzyme: argininosuccinate synthetaseCitrullineLess than 1 in 100,000 birthsConsultation with a dietician; low-protein diet supplemented by special medical foods and formulaPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Early treatment can help prevent high ammonia levels. Accumulation of ammonia can cause brain damage, resulting in lifelong learning problems, mental retardation, or lack of coordination.
• HomocystinuriaDeficiency of or nonfunctioning enzyme: cystathionine beta-synthaseMethionineLess than 1 in 100,000 births (found more often in white people from the New England region of the United States and in people of Irish ancestry)Consultation with dietician; diet low in methionine supplemented by special medical foods; administration of vitamin B6, vitamin B12, folic acid, betaine, and L-cystinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Treatment may lower the chance for blood clots, heart disease, and stroke. Treatment also lessens the chance of eye problems such as cataract or lens dislocation, which can often be corrected by surgery.
• Maple syrup urine disease (MSUD)Deficiency of or nonfunctioning enzyme group: branched-chain ketoacid dehydrogenaseLeucine and isoleucineLess than 1 in 100,000 births (found more often in Mennonite people in certain parts of the United States: about 1 in 380 babies of Mennonite background is born with MSUD; also found more often in people of French-Canadian ancestry)Consultation with a dietician; diet low in branched-chain amino acids supplemented by special medical foods and formula, administration of thiamine; liver transplantPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Untreated or delayed treatment results in brain damage and mental retardation.
• PhenylketonuriaDeficiency of or nonfunctioning enzyme: phenylalanine hydroxylase (PAH)Phenylalanine1 in 10,000–15,000 birthsConsultation with a dietician; diet low in phenylalanine supplemented by special medical foods and formula; administration of BH4 (tetrahydrobiopterin), which helps the PAH enzyme convert phenylalanine into tyrosine. Patients with this condition should avoid foods and vitamins containing the sugar substitute aspartame, which increases blood levels of phenylalaninePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Some patients may experience delays in learning even after treatment, but without treatment or if treatment is delayed until after 6 mo of age, mental retardation usually results.
• Tyrosinemia type 1Deficiency of or non-functioning enzyme: fumarylacetoacetaseTyrosineLess than 1 in 100,000 births (found more often in people of French-Canadian ancestry)Consultation with a dietician; diet low in tyrosine and phenylalanine supplemented by special medical foods and formula; administration of nitisinone to prevent liver and kidney damage; liver transplantPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Without treatment, liver and kidney damage will occur.
Inborn errors of fatty acid metabolism
• Carnitine uptake disorderDeficiency of or nonfunctioning enzyme: carnitine transporterFree and total carnitineLess than 1 in 100,000 birthsConsultation with a dietician; diet low in tyrosine and phenylalanine supplemented by special medical foods and formulaPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Without treatment, infants may incur brain damage resulting in permanent learning disabilities or mental retardation.
• Long-chain L-3-hydroxyacyl-CoA dehydrogenase deficiencyDeficiency of or non-functioning enzyme: long-chain L –3-hydroxyacyl-CoA dehydrogenaseAcylcarnitinesGreater than 1 in 75,000 births (found more often in people of Finnish ancestry)Consultation with a dietician; low-fat, high-carbohydrate diet supplemented by special medical foods and formula consumed in small, frequent meals to avoid hypoglycemia; infants may need to be woken up to eat if they do not wake up on their own; administration of medium-chain triglyceride oil (MCT oil), L-carnitine and DHA (docosahexanoic acid) which may help prevent loss of eyesightPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Continued episodes of hypoglycemia can lead to learning disabilities or mental retardation. With treatment, some people still develop vision, muscle, liver or heart problems.
• Medium-chain acyl-CoA dehydrogenase deficiencyDeficiency of or nonfunctioning enzyme: medium-chain acyl-CoA dehydrogenaseOctanoyl carnitine and acyl carnitineGreater than 1 in 25,000 births (found more often in white people from Northern Europe and the United States)Consultation with a dietician; low-fat, high-carbohydrate diet supplemented by special medical foods and formula consumed in small, frequent meals to avoid hypoglycemia; infants may need to be woken up to eat if they do not wake up on their own; administration of MCT oil and L-carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Continued episodes of hypoglycemia can lead to lack of coordination, chronic muscle weakness, learning disabilities, or mental retardation.
• Trifunctional protein (TFP) deficiencyDeficiency of or nonfunctioning enzyme group: mitochondrial trifunctional protein3-hydroxy-hexadecanoylcarnitineLess than 1 in 100,000 birthsConsultation with a dietician; low-fat, high-carbohydrate diet supplemented by special medical foods and formula consumed in small, frequent meals to avoid hypoglycemia; infants may need to be woken up to eat if they do not wake up on their own; administration of MCT oil and L-carnitineMost newborns with early TFP deficiency die of cardiac or respiratory problems, even when treated. Patients with childhood TFP deficiency who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Continued episodes of hypoglycemia can lead to lack of coordination, chronic muscle weakness, learning disabilities, or mental retardation. Patients with mild/muscle TFP deficiency who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. This form does not affect intelligence.
• Very-long-chain acyl-CoA dehydrogenase deficiencyDeficiency of or non-functioning enzyme: very-long-chain acyl-CoA dehydrogenaseTetradecenoylcarnitineGreater than 1 in 75,000 birthsConsultation with a dietician; low-fat, high-carbohydrate diet supplemented by special medical foods and formula consumed in small, frequent meals to avoid hypoglycemia; infants may need to be woken up to eat if they do not wake up on their own; administration of MCT oil and L-carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development.
Inborn errors of organic acid metabolism
• Glutaric acidemia Type 1Deficiency of or nonfunctioning enzyme: glutaryl-CoA dehydrogenaseGlutarylcarnitineGreater than 1 in 75,000 births (found more often in people of Amish background in the United States, the Ojibway Indian population in Canada, and people of Swedish ancestry)Consultation with a dietician; diet high in carbohydrates, low in protein, especially lysine and tryptophan, supplemented by special medical foods and formula consumed in small, frequent meals; administration of riboflavin, carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development.
• 3-hydroxy, 3-methylglutaric aciduriaDeficiency of or nonfunctioning enzyme: HMG CoA lyaseAcylcarnitinesLess than 1 in 100,000 births (found more often in people of Saudi Arabian, Portuguese, and Spanish ancestry)Consultation with a dietician; diet high in carbohydrates, low in protein, especially leucine, supplemented by special medical foods and formula consumed in small, frequent meals; administration of carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development.
• Isovaleric acidemiaDeficiency of or non-functioning enzyme: isovaleryl-CoA dehydrogenaseIsovaleryl carnitineLess than 1 in 100,000 birthsConsultation with a dietician; diet high in carbohydrates, low in protein, especially leucine, supplemented by special medical foods and formula consumed in small, frequent meals; administration of glycine, carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development.
• Methyl malonic acidemias (vitamin B12 disorders)Deficiency of or non-functioning enzyme: methylmalonyl-CoA mutase combined with mutations causing defects in vitamin B12 metabolismPropionylcarnitineLess than 1 in 100,000 birthsConsultation with a dietician; diet high in carbohydrates, low in protein, especially leucine, valine, methionine, and threonine, supplemented by special medical foods and formula consumed in small, frequent meals; administration of betaine, carnitine, vitamin B12Treatment may help some patients but not others. Some infants die even with treatment. Patients who begin treatment soon after birth and continue treatment throughout life may have permanent learning disabilities, psychiatric disorders, or mental retardation.
• Beta ketothiolaseDeficiency of or nonfunctioning enzyme: mitochondrial acetoacetyl-CoA thiolase3-methylcrotonyl carnitineLess than 1 in 100,000 birthsConsultation with a dietician; diet high in carbohydrates, low in protein, supplemented by special medical foods and formula consumed in small, frequent meals; administration of carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development.
• Methyl malonic acidemias (methylmalonyl-CoA mutase)Deficiency of or nonfunctioning enzyme: methylmalonyl-CoA mutasePropionylcarnitineLess than 1 in 75,000 birthsConsultation with a dietician; diet high in carbohydrates, low in protein, supplemented by special medical foods and formula consumed in small, frequent meals; administration of carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Some patients, even with treatment, may have seizures, involuntary movement disorders, kidney failure, permanent learning disabilities, or mental retardation. Children who are not treated until after they have symptoms may have lasting physical and learning problems.
• Proprionic acidemiaDeficiency of or nonfunctioning enzyme: propionyl-CoA carboxylaseAcylcarnitinesGreater than 1 in 75,000 births (found more often in people of Saudi Arabian ancestry and the Inuit Indian population of GreenlandConsultation with a dietician; diet high in carbohydrates, low in protein, especially leucine, valine, methionine, and threonine, supplemented by special medical foods and formula consumed in small, frequent meals; administration of biotin, carnitinePatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Some patients, even with treatment, may have seizures, involuntary movement disorders, chronic infections, permanent learning disabilities, or mental retardation.
• Multiple carboxylaseDeficiency of or non-functioning enzyme: 3-methylcrotonyl-CoA carboxylase, 2-methylbutyryl-CoA dehydrogenase3-hydroxy-isovaleryl carnitineLess than 1 in 100,000 birthsConsultation with a dietician; diet high in carbohydrates, low in protein, supplemented by special medical foods and formula consumed in small, frequent meals; administration of carnitinePatients who begin treatment soon after birth and continue treatment through out life usually have normal growth and development.
Other multisystem diseases
• Biotinidase deficiencyDeficiency of or nonfunctioning enzyme: biotinidaseBiotinidaseGreater than 1 in 75,000 birthsConsultation with a dietician; diet supplemented by special medical foods and formula; administration of biotinPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development.
• Cystic fibrosisDeficiency of or nonfunctioning protein: cystic fibrosis transmembrane conductance regulator proteinCF mutation analysis or immunoreactive trypsinogenGreater than 1 in 5,000 birthsConsultation with a dietician; higher calorie diet supplemented by special medical foods and formula, additional hydration, administration of pancreatic enzymes and vitamins; bronchodilators, antibiotics, mucus thinners; percussive therapy, ThAIRapy vest; gene therapy, lung transplantPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. The goal with treatment is to lessen symptoms. Treatment cannot cure the condition. Symptoms may occur in spite of good treatment.
Core Conditions Evaluated in Many states
• Galactosemia (classical)Deficiency of or nonfunctioning enzyme: galactose-1-phosphate uridyl transferaseGalactose-1-phosphateGreater than 1 in 50,000 birthsConsultation with a dietician; diet free of lactose and galactose supplemented by special medical foods and formula; administration of calcium, vitamin D, and vitamin KPatients who begin treatment soon after birth and continue treatment throughout life usually have normal growth and development. Some patients may experience delays in learning even after treatment, but without treatment or if treatment is delayed until after 10 days of age, developmental delays and learning disabilities usually result.

This procedure is contraindicated for

    N/A

Indications

    Hearing Tests

  • Screen for hearing loss in infants to determine the need for a referral to an audiologist
  • Blood Spot testing

  • Assist in the diagnosis of CAH
  • Assist in the diagnosis of congenital hypothyroidism
  • Assist in the diagnosis of abnormal hemoglobins as with Hgb C disease, sickle cell trait or sickle cell disease, and thalassemias, especially in patients with a family history positive for any the disorders
  • Assist in identifying the cause of hemolytic anemia resulting from G-6–PD enzyme deficiency
  • Detect congenital errors of amino acid, fatty acid, or organic acid metabolism
  • Detect congenital errors responsible for urea cycle disorders
  • Screen for multisystem disorders such as CF, biotinidase deficiency, or galactosemia
  • Test for HIV antibodies in infants who have documented and significant exposure to other infected individuals

Potential diagnosis

Abnormal findings related to

    Hearing Test

  • Abnormal audiogram (related to congenital damage or malformations of the inner ear, infections, residual amniotic fluid or vernix in the ear canal)

Endocrine Disorders

Increased in

  • Congenital hypothyroidism (TSH) (related to decrease in total thyroxine hormone levels, which activates the feedback loop to increase production of TSH)
  • CAH (adrenocorticotropic hormone [ACTH] and androgens) (related to an autosomal recessive inherited disorder that results in missing or malfunctioning enzymes responsible for the production of cortisol and which may result in a salt-wasting condition or virilization of female genitalia)

Decreased in

    Congenital hypothyroidism (total T4) (related to missing or malfunctioning thyroid gland resulting in absence or decrease in total thyroxine hormone levels) CAH (21-hydroxylase) (related to an autosomal recessive inherited disorder that results in missing or malfunctioning enzymes responsible for the production of cortisol and which may result in one of several conditions, including a salt-wasting condition or virilization of female genitalia) CAH (cortisol) (related to an autosomal recessive inherited disorder that results in missing or malfunctioning enzymes responsible for the production of cortisol and which may result in a salt-wasting condition or virilization of female genitalia) CAH (aldosterone) (related to an autosomal recessive inherited disorder that results in missing or malfunctioning enzymes responsible for the production of cortisol and which may result in a salt-wasting condition)

Abnormal findings related to

    Hemoglobinopathies

  • Hgb S: sickle cell trait or sickle cell anemia (most common variant in the United States; occurs with a frequency of about 8% among African Americans) (related to an autosomal recessive inherited disorder that results in a genetic variation in the β-chain of hemoglobin, causing a conformational change in the hemoglobin molecule and affecting the oxygen-binding properties of hemoglobin, which results in sickle-shaped red blood cells)
  • Hgb SC disease (related to an autosomal recessive inherited disorder that results in the presence of an abnormal combination of Hgb S with Hgb C and presents a milder form of sickle cell anemia)
  • Hgb S/β-thalassemias (related to an autosomal recessive inherited disorder that results in the presence of abnormal hemoglobin S/β-thalassemia, which combines the effects of thalassemia, a genetic disorder that results in decreased production of hemoglobin and sickle cell anemia, where sickled red blood cells lack the ability to combine effectively with oxygen)

RBC Enzyme Defect

Decreased in

    G6PD deficiency (usually related to an X-linked recessive inherited disorder that results in a deficiency of glucose-6-phosphate dehydrogenase, which causes a hemolytic anemia)

Inborn Errors of Amino Acid Metabolism/Disorders of the Urea Cycle

Aminoacidopathies (usually related to an autosomal recessive inherited disorder that results in insufficient or nonfunctional enzyme levels; specific amino acids are implicated) Disorders of the urea cycle; specifically argininemia, argininosuccinic acidemia, citrullinemia, and hyperammonemia/hyperornithinemia/homocitrullinemia (usually related to an autosomal recessive inherited disorder that results in insufficient or nonfunctional enzyme levels; specific amino acids are implicated)

Inborn Errors of Organic Acid Metabolism

Organic acid disorders (usually related to an autosomal recessive inherited disorder that results in insufficient or nonfunctional enzyme levels; specific organic acids are implicated)

Inborn Errors of Fatty Acid Metabolism

Fatty acid oxidation disorders (usually related to an autosomal recessive inherited disorder that results in insufficient or nonfunctional enzyme levels; specific fatty acids are implicated)

Other Multisystem Diseases

Biotinidase deficiency (related to an autosomal recessive inherited disorder that results in deficiency of the enzyme biotinidase, which prevents absorption or recycling of the essential vitamin biotin) Cystic fibrosis (related to an autosomal recessive inherited disorder that results in insufficient or nonfunctional CF transmembrane conductance regulator protein, which results in poor transport of salts, especially sodium and chloride, and significantly impairs pulmonary and gastrointestinal function) Galactosemia (classical) (usually related to an autosomal recessive inherited disorder that results in insufficient or nonfunctional galactose-1-phosphate uridyl transferase enzyme levels

Infectious Diseases

Positive findings in:

  • HIV-1 or HIV-2 infection

Critical findings

    N/A

Interfering factors

  • Specimens for newborn screening collected earlier than 24 h after the first feeding or collected from neonates receiving total parenteral nutrition may produce invalid results.
  • Specimens for newborn screening that are improperly applied to the filter paper circles may produce invalid results.
  • Touching blood spots after collection on the filter paper card may contaminate the sample and produce invalid results.
  • Failure to let the filter paper sample dry may affect test results.
  • Specimens for newborn screening collected after transfusion may produce invalid results.
  • Nonreactive HIV test results occur during the acute stage of the disease, when the virus is present but antibodies have not sufficiently developed to be detected. It may take up to 6 mo for the test to become positive. During this stage, the test for HIV antigen may not confirm an HIV infection.

Nursing Implications and Procedure

Potential nursing problems

ProblemSigns & SymptomsInterventions
Fear (Related to diagnosed congenital anomaly of newborn; newborn disease; possibility infant death [HIV, sickle cell, etc.])Expression of fear; expresses concern over caring for a disabled child; preoccupation with fear; increased tension; increased blood pressure; increased heart rate; vomiting; diarrhea; nausea; fatigue; weakness; insomnia; shortness of breath; increased respiratory rate; withdrawal; panic attacksProvide access to social services; provide specific and culturally appropriate education; assist the patient and family to recognize effective coping strategies; assist the patient to acknowledge his or her fear; provide a safe environment to discuss fear; explore cultural influences that may enhance fear
Knowledge (Related to diagnosis of childhood disability or disease; complexity of treatment; poor understating of provided information; cultural or language barriers; anxiety; emotional disturbance; unfamiliar with medical management) Lack of interest or questions; multiple questions; anxiety in relation to disease process and management, including management of disabled child; verbalizes inaccurate information; lack of follow through with directionsIdentify patient’, family’s, and significant othersߣ concerns about childߣs diagnosed disease or disability; provide information and support group information on caring for a disabled child; provide information on treatment options related to disease or disability (hearing loss, sickle cell anemia, etc.); refer to online legitimate evidence-based sources for review; provide information related to genetic counseling
Nutrition (Related to inability to metabolize galactose)Lethargy; weight loss; failure to thrive; jaundice; bleeding; developmental delays; speech delays; irritability; convulsionsProvide information for use of lactose-free formula, soy formula, or a protein-based hydrolysate formula; ensure strict avoidance of dairy products, organ meats, MSG, foods with sodium or calcium caseinate, any processed food that includes margarine as an ingredient, and any fermented soy sauce, once off of formula and on a regular diet
Infection (Related to infant exposure in utero secondary to maternal HIV disease [maternal fetal transmission]; infected mother breastfeeding)Positive polymerase chain reaction testing in infants; delay in developmental milestones (walking, crawling, etc.) in toddlers; school-age children perform poorly; possible neurologic problems with ongoing diseaseAdminister ordered antiretroviral medication or prescribed treatment modality; discuss family support for treatment of the child and mother; assess infection in other family members and children; educate about the importance of adhering to treatment modalities; consider individual cultures and socioeconomic strategies to foster positive outcomes

Pretest

    General

  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Education regarding newborn screening should begin during the prenatal period and be reinforced at the time of preadmission testing. Many birthing facilities and hospitals provide educational brochures to the parents. Physicians and physician delegates are responsible to inform parents of the newborn screening process before discharge. Inform the patient these procedures can assist in evaluating a number of congenital conditions, including hearing loss, thyroid function, adrenal gland function, and other metabolic enzyme disorders. Evaluation may also include HIV antibody testing if not performed prenatally or if otherwise clinically indicated.
  • Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a history of the patient’s endocrine system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Blood Tests

  • Review the procedure with the parents or caregiver. Explain that blood specimens from neonates are collected by heel stick and applied to filter paper spots on the birth state’s specific screening program card.
  • Hearing Test

  • Review the procedure with the parents or caregiver. Address concerns about pain and explain that no discomfort will be experienced during the test. Inform the parents or caregiver that an audiologist or HCP trained in this procedure performs the test in a quiet room and that the test can take up 20 min to evaluate both ears. Explain that each ear is tested separately by using earphones and/or a device placed behind the ear to deliver sounds of varying intensities.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Most state regulations require screening specimens to be collected between 24 and 48 hr after birth to allow sufficient time after protein intake for abnormal metabolites to be detected, and preferably before blood product transfusion or physical transfer to another facility.

Intratest

  • Potential complications: N/A
  • Hearing Test

  • Perform otoscopy examination to ensure that the external ear canal is free from any obstruction (see monograph titled “Otoscopy”).
  • Test for closure of the canal from the pressure of the earphones by compressing the tragus. Tendency for the canal to close (often the case in children and elderly patients) can be corrected by the careful insertion of a small, stiff plastic tube into the anterior canal.
  • Start the test by providing a trial tone of 15 to 20 dB above the expected threshold to the ear for 1 to 2 sec to familiarize the patient with the sounds. If no response is indicated, the level is increased until a response is obtained, and then it is raised in 10-dB increments or until the audiometer’s limit is reached for the test frequency. The test results are plotted on a graph called an audiogram using symbols that indicate the ear tested and responses using earphones (air conduction) or oscillator (bone conduction).
  • Air Conduction

  • In the air conduction test, the tone is delivered to an infant through insert earphones or ear muffins, and the auditory response is measured through electrodes placed on the infant’s scalp. Air conduction is tested first by starting at 1,000 Hz and gradually decreasing the intensity 10 dB at a time until there is no response, indicating that the tone is no longer heard. The intensity is then increased 5 dB at a time until the tone is heard again. This is repeated until the same response is achieved at a 50% response rate at the same hertz level. The threshold is derived from the lowest decibel level at which the patient correctly responds to three out of six trials to a tone at that hertz level. The test is continued for each ear with tones delivered at 1,000 Hz, 2,000 Hz, 4,000 Hz, and 8,000 Hz, and then again at 1,000 Hz, 500 Hz, and 250 Hz to determine a second threshold. Results are recorded on a graph called an audiogram. Averaging the air conduction thresholds at the 500-Hz, 1,000-Hz, and 2,000-Hz levels reveals the degree of hearing loss and is called the pure tone average (PTA).
  • Bone Conduction

  • Bone conduction testing is performed in a similar manner to air conduction testing; a vibrator placed on the skull is used to deliver tones to an infant instead of earphones as in the air conduction test. The raised and lowered tones are delivered as in air conduction using 250 Hz, 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz to determine the thresholds. An analysis of thresholds for air and bone conduction tones is done to determine the type of hearing loss (conductive, sensorineural, or mixed).
  • Otoacoustic Emissions

  • In otoacoustic testing, microphones are placed in the infant’s ears. Nearby sounds should echo in the ear canal and be detected by the microphones if the infant’s hearing is normal.
  • Filter Paper Test

  • Obtain kit and cleanse heel with antiseptic. Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Use gauze to dry the stick area completely. Perform heel stick, gently squeeze infant’s heel, and touch filter paper to the puncture site. When collecting samples for newborn screening, it is important to apply each blood drop to the correct side of the filter paper card and fill each circle with a single application of blood. Overfilling or underfilling the circles will cause the specimen card to be rejected by the testing facility. Additional information is required on newborn screening cards and may vary by state. Newborn screening cards should be allowed to air dry for several hours on a level, nonabsorbent, unenclosed area. If multiple patients are tested, do not stack cards. State regulations usually require the specimen cards to be submitted within 24 hr of collection. Observe/assess puncture site for bleeding or hematoma formation, and secure gauze with adhesive bandage.

Post-Test

  • Inform the parent or caregiver that a report of the results will be made available to the requesting HCP, who will discuss the results with the parents or caregiver.
  • Nutritional Considerations: Instruct the parents or caregiver in special dietary modifications to treat deficiency, and refer parents or caregiver to a qualified nutritionist, as appropriate. Amino acids are classified as essential (i.e., must be present simultaneously in sufficient quantities), conditionally or acquired essential (i.e., under certain stressful conditions, they become essential), and nonessential (i.e., can be produced by the body, when needed, if diet does not provide them). Essential amino acids include lysine, threonine, histidine, isoleucine, methionine, phenylalanine, tryptophan, and valine. Conditionally essential amino acids include cysteine, tyrosine, arginine, citrulline, taurine, and carnitine. Nonessential amino acids include alanine, glutamic acid, aspartic acid, glycine, serine, proline, glutamine, and asparagine. A high intake of specific amino acids can cause other amino acids to become essential.
  • Social and Cultural Considerations: Recognize anxiety related to test results, and be supportive of parents’ or caregiver’s perceived loss of impaired activity or independence related to hearing loss or physical limitations and their fear of shortened life expectancy for the newborn. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the parents or caregiver regarding access to genetic or other counseling services. Provide contact information, if desired, for the March of Dimes (www.marchofdimes.com), the National Library or Medicine (www.nlm.nih.gov/medlineplus/newbornscreening.html), general information (newbornscreening.info/Parents/facts.html), or the state department of health newborn screening program. There are numerous support groups and informational Web sites for specific conditions, including the National Center for Hearing Assessment and Management (www.infanthearing.org), the American Speech-Language-Hearing Association (www.asha.org), ABLEDATA (for assistive technology; sponsored by the National Institute on Disability and Rehabilitation Research [www.abledata.com]), the Sickle Cell Disease Association of America (www.sicklecelldisease.org), the Fatty Oxidation Disorders (FOD) Family Support Group (www.fodsupport.org), the Organic Acidemia Association (www.oaanews.org), the United Mitochondrial Disease Foundation (www.umdf.org), the Cystic Fibrosis Foundation (www.cff.org), and, for AIDS information, the National Institutes of Health (www.aidsinfo.nih.gov) and the CDC (www.cdc.gov).
  • Social and Cultural Considerations: Inform parents or caregiver that positive neonatal HIV findings must be reported to local health department officials.
  • Social and Cultural Considerations: Offer support, as appropriate, to parents who may be the victims of rape or sexual assault. Educate the parents regarding access to counseling services. Provide a nonjudgmental, nonthreatening atmosphere for a discussion during which risks of sexually transmitted diseases to the newborn are explained. It is also important to discuss problems the parents may experience (e.g., guilt, depression, anger).
  • Depending on the results of these procedures, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
  • Patient Education

    • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
    • Answer any questions or address any concerns voiced by the parents, family, or caregiver.
    • Provide information regarding vaccine-preventable diseases where indicated (e.g., diphtheria, hepatitis B, measles, mumps, pertussis, polio, rotavirus, rubella, varicella). Provide contact information, if desired, for the Centers for Disease Control and Prevention (www.cdc.gov/vaccines/vpd-vac).
  • Expected Patient Outcomes

      Knowledge

    • The parent or caregiver states understanding of the importance of alternate language training (sign language) for an infant with hearing loss as soon as possible to enhance growth and development
    • The parent or caregiver states understanding that failure to refrain from feeding the child foods that include galactose can result in severe disability and death
    • Skills

    • The parent or caregiver demonstrates proficiency of accessing online resources as a source of ongoing information
    • The parent or caregiver develops a diet free of dairy products to support the childߣs health maintenance
    • Attitude

    • The parent or caregiver agrees to genetic counseling prior to having another child in identify risk of future disability in additional children
    • The parent or caregiver agrees to adhere to HIV treatment plan for self and child

Related Monographs

  • Related tests include amino acid screen, amniotic fluid analysis, audiometry hearing loss, biopsy chorionic villus, chloride sweat, chromosome analysis, CBC, evoked brain potential studies for hearing loss, glucose-6–phosphate dehydrogenase, hemoglobin electrophoresis, human immunodeficiency virus type 1 and type 2 antibodies, otoscopy, sickle cell screen, TSH, thyroxine total, and US thyroid.
  • Refer to the Auditory, Endocrine, Genitourinary, Hematopoietic, Hepatobiliary, and Reproductive systems tables at the end of the book for related tests by body system.
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