From the moment a baby is born, a number of key tests are done to make sure the infant is healthy. Here is an explanation of the major ones:
White Blood Count
Bacterial infections in newborns can have devastating results since this illness appears quickly, often without warning or symptoms. Many times there is only the history of fever in the mother, the presence of foul smelling amniotic fluid at delivery, or a nursery nurse who reports that the infant “just doesn’t look right.” When an infection is suspected, a white blood count (done as part of a CBC – complete blood count) is obtained from a small amount of blood. The total numbers of white cells are reported along with the different types of white cells present. Too many immature white cells in proportion to the total number of white cells may be an early warning sign of an infection. Antibiotics are often started simply on the basis of the child’s history and the elevation of the white blood count, and continued until blood culture results are available.
Before discharge, the newborn will be screened for certain birth defects. While these conditions have no visible effects on the baby, they can cause severe problems if not detected and treated.
Low blood glucose is fairly common in newborns. Extremely low levels are found in premature infants, babies small for their gestational age, and infants born to diabetic mothers. In the latter case, increased insulin in the baby’s blood can drive the newborn’s blood sugar down to dangerous levels. Low blood sugar in babies is a medical emergency that can result in seizures and neurological damage if not treated.
In theUnited Statesand many other countries, phenylketonuria is detected by newborn screening, and individuals who are appropriately treated (eg, with a diet low in phenylalanine and/or tetrahydrobiopterin) can have normal intelligence and lead a normal life. Elevated phenylalanine levels negatively impact cognitive function, and individuals with classic phenylketonuria almost always have intellectual disability unless levels are controlled through dietary or pharmacologic treatment.