In the United States, before mother and her newborn baby leave the hospital, the baby has blood drawn by means of a procedure commonly called a "heel stick test." A small amount of blood is drawn by pricking the baby's heel, and the blood is used to test for a variety of hereditary endocrine, metabolic and blood disorders. Some tests are required in all U.S. states, while other tests vary state by state.
Phenylketonuria (PKU)
An enzyme called hepatic phenylalanine hydroxylase is required for the body to metabolize phenylalanine (Phe)---an amino acid present in nearly all foods---into another amino acid known as tyrosine. A build-up of Phe in the system can lead to brain damage, seizures and severe mental retardation. Treatment consists of a special formula for the baby. Later on, a low-protein diet requiring vitamin and mineral supplements is necessary, and this special diet must be followed for life. Early detection is critical; therefore, a PKU test is required for all infants born in the United States.
Congenital Hypothyroidism (CH)
Also called neonatal hypothyroidism, CH is a condition in which the thyroid gland of the newborn is deficient. Common causes of this disorder include abnormal or missing thyroid gland, failure of the pituitary gland to trigger the thyroid gland and impaired production of thyroid hormones. A partial or abnormally formed thyroid gland is the most commonly occurring defect, affecting one out of approximately 3,000 births. CH occurs twice as often in girls as in boys.
Galactosemia (GALT)
A hereditary enzyme disorder, galactosemia describes the body's inability to metabolize a simple sugar known as galactose. If galactose is not used, it builds up in the body. Severe damage to the central nervous system, liver, kidneys and eyes can result. Galactose is a component of lactose, which is the sugar found in milk. Human and animal milk cannot be tolerated by persons with this condition. Detection immediately after birth can prevent serious, irreversible problems in newborns such as cataracts, mental retardation and cirrhosis of the liver.
Hearing
Newborns are routinely screened for hearing problems before leaving the hospital. Impaired hearing, if left undetected, can lead to language acquisition, learning and behavioral difficulties as the child grows. The infant is given two tests: an otoacoustic emissions (OAE) test and an auditory brainstem response (ABR) test. These non-invasive tests are conducted using special earphones and electrodes; they are painless and require no response on the part of the infant. If the newborn is fussy, he may be given a very mild sedative in order to keep him relaxed, still and quiet while the tests are being performed.
Infant Testing for Other Genetic Disorders
In the United States, additional tests on newborns vary from state to state, and even from hospital to hospital. Certain tests may be performed on infants with specific ethnic backgrounds, such as sickle cell anemia tests for children of African descent and testing for Tay-Sachs disease in children of Eastern European Jewish descent. The March of Dimes recommends a minimum battery of 29 tests, including those previously mentioned. March of Dimes newborn screening recommendations also include tests for HIV, cystic fibrosis and thalassemia, among other disorders.
Tags: thyroid gland, United States, amino acid, blood drawn, March Dimes, mental retardation
