Routine evaluation of a newborn includes a number of laboratory tests. These tests are valuable because they have the potential to identify diseases and disorders before symptoms appear and before serious complications arise. Early detection allows treatment that may prevent development of serious health problems.
Various conditions that may be present at birth (congenital) can affect the health and wellness of a newborn. Most of these conditions are rare, though some are more prevalent in certain families. Disorders range from difficulties a newborn may have processing certain nutrients (metabolic) to problems with hormones (endocrine) to the production of abnormal forms of hemoglobin, the oxygen-carrying protein in red blood cells. Some of these conditions cannot be cured, but many can be managed so that the child can grow and live a relatively normal life.
Newborns can be routinely screened for many of these disorders before leaving the hospital using a few drops of blood.
Newborn screening tests help to identify potentially treatable or manageable congenital disorders within days of birth. Life-threatening health problems, mental retardation and serious lifelong disabilities can be avoided or minimized if a condition is quickly identified and treated.
Screening tests recommended for all newborns
Recommends that all newborns be screened for 31 core disorders and 26 secondary disorders. The tests are organized into broad categories:
Reminders to parents : Newborn screening tests are usually performed within 24 to 48 hours of life. For some tests, such as phenylketonuria (PKU) and congenital hypothyroidism (CH), it is important that they not be run too soon after birth. They may not accurately reflect whether a disorder is present if performed within the first 24 hours of life. Since women and their newborns may be discharged within a day or two of the birth, it is possible that a newborn could be tested with a sample taken within those first 24 hours or recommend screening two times, once in the hospital and then about 2 weeks later.
Screening for inherited disorders in newborns at risk
testing typically involves detecting the specific gene(s) associated with a disorder that occurs frequently within a family or members of a specific ethnic group. Parents may decide to ask for supplemental tests for their newborn in these situations:
In some cases, one or both of the parents can be tested before or during a pregnancy to determine if they are carriers of these gene-based disorders. Amniotic fluid can also sometimes be tested during the pregnancy.
Genetic tests can be run on blood, other types of body fluids, and tissues. For some conditions, chromosomes are examined for abnormalities; for other diseases, a single gene is analyzed. It should be noted that some genetic tests will identify a condition for which there is no treatment or cure and no changes can be made to improve the child's quality of life. The value of such test results is controversial.
Typically, newborns are tested for infectious diseases only if they show signs and symptoms. However, asymptomatic newborns may be screened for HIV or hepatitis B if their mothers have the disease or were not screened for the infection while pregnant. Some states require that all newborns be tested for HIV.
Human immunodeficiency virus is the virus that causes AIDS (acquired immunodeficiency syndrome). The infection can pass from an infected mother to her child during pregnancy, delivery, or breastfeeding.
Almost all AIDS cases in children result from mother-to-baby transmission. If a mother with HIV does not receive treatment during the pregnancy, the child has a 1 in 4 chance of getting HIV. With timely treatment, however, fewer than 2% of children of infected mothers get the virus.
The best way to protect the child's health is to detect the HIV infection during pregnancy, treat the mother with medication, and make birthing plans to help the baby avoid infection (such as a C-section rather than vaginal birth).
If the mother was not tested during the pregnancy or at the time of the delivery, the newborn can be screened and, if positive, treated shortly after birth. HIV testing has become routine prenatal care in some countries.
It is recommended that a pregnant woman be screened for hepatitis B infection either before or early in her pregnancy, and again in the third trimester if she participates in activities that put her at increased risk, such as unprotected sexual contact or intravenous drug use. Infection with the hepatitis B virus causes an inflammation of the liver. It is important to detect active hepatitis B infections in pregnant women because newborns are especially vulnerable to developing chronic infection, which can over the course of many years cause progressive liver damage. If a hepatitis infection is detected in a pregnant woman, she can be monitored and the baby can receive treatment at birth to minimize the risk of developing hepatitis B.
With the advent of screening pregnant women for hepatitis B and the vaccination of newborns, the number of infected babies has fallen. However, a newborn may be screened if there is concern that the mother is at high risk of infection and/or she was not tested during the pregnancy.