Newborn screening: Tests of newborns to screen for serious treatable diseases most of which are
genetic. The newborn screening tests done in the United States are decided on a state-by-state
basis. The most common newborn screening tests in the US include those
for hypothyroidism(underactivity of the thyroid gland), PKU (phenylketonuria), galactosemia,
and sickle cell disease. Testing for hypothyroidism and PKU is required in virtually all States.
Screening for galactosemia and sickle cell disease is required in most states. Some states in the US
mandate tests for other conditions. These include: maple syrup urine disease (MSUD),
homocystinuria, biotinidase deficiency, congenital adrenal hyperplasia, MCAD, tyrosinemia, cystic
fibrosis, and toxoplasmosis. All these tests are usually done using the same sample of the baby's
blood.