How Is Jaundice Measured in Infants?

Significance

Jaundice is caused by an excess of bilirubin, a yellow-orange pigment in the blood resulting from the normal breakdown of hemoglobin in red blood cells. The more the disintegration of red blood cells, the higher the concentration of bilirubin.

Physiological jaundice of the newborn is common. Jaundice occurs most often in preterm infants born before the 36th week and premature babies weighing less than five pounds. Because the excess red blood cells babies are born with are being broken down, the infant's liver is not mature enough to process the extra bilirubin being produced. In some cases, jaundice may be due to hemolytic disease, occurring when the mother and baby have different blood types. Faster breakdown of red blood cells will take place in this circumstance, resulting in elevated bilirubin levels.

Identification

Initial diagnosis of infant jaundice is based on the baby's appearance. The excess pigment in the blood causes a yellowish discoloration of the skin and eyes. In most instances, the bilirubin levels fall to normal within a few days as the overabundance of red blood cells diminishes and the liver matures.

Procedure

In infants, increased levels of bilirubin can lead to brain damage and hearing loss. The doctor will order a blood test. A lab technician will prick the baby's heel and gently squeeze blood into a test tube. The sample of blood is taken to the laboratory. Cells are separated from the liquid serum. The test is performed on the serum to determine the concentration of bilirubin. Charted norms are used that identify the specific age of the infant in hours and the bilirubin level. The chart, called a Bhutani nomogram, predicts the likelihood of the infant to produce even higher concentrations or the probability that the levels will diminish safely on their own. In a newborn, the specific amount of bilirubin in the blood is not significant on its own. The time line established by the nomogram determines the risk for acquiring forthcoming severe or acute levels.

Types

Prior to reaching the liver, bilirubin is referred to as indirect, or unconjugated, and does not dissolve in liquid. Direct, or conjugated, bilirubin has been processed by the liver into soluble form. It is then released as bile and stored in the gall bladder until it is excreted into the large intestine to be eliminated from the body.

Treatment

Phototherapy, treatment with a special blue light, is prescribed for babies with high levels. The light alters the composition of the bilirubin, enabling the liver to process the pigment more effectively. Emphasis is placed on good nourishment through successful breastfeeding. In rare cases, blood transfusions are warranted.