According to researchers at The Children’s Hospital of Philadelphia and the Hospital of the University of Pennsylvania, a simple test can accurately predict which newborn babies are more likely to develop severe hyperbilirubinemia (dangerous levels of jaundice).

Most newborns develop jaundice, but it is usually mild and seldom leads to serious consequences, except in a small number of babies. After birth, red blood cells breakdown and release a substance called bilirubin. Jaundice occurs when the bilirubin accumulates in the blood causing the skin to appear yellow. Researchers have theorized that small amounts of bilirubin in the blood may be beneficial, but large amounts can cause brain damage and even death.

Currently, there are two ways to assess a newborn’s risk of developing severe hyperbilirubinemia: measuring the bilirubin level prior to hospital discharge and performing a systematic review of risk factors such as method of infant feeding, history of jaundice with prior siblings, and ethnicity. The American Academy of Pediatrics recommends that one or both methods be used for all newborns.

Keren and colleagues conducted a prospective study of 823 term and near-term newborns. They compared the effectiveness of a predischarge (<52 hours) bilirubin measurement, assessment of risk factors, and a combination of the two (predischarge measurement and assessment of additional risk factors). Risk factors for significant hyperbilirubinemia were obtained from the patient record, parent interview, and nurse assessment prior to discharge. Transcutaneous bilirubin measurements were taken each day while the newborns were in the hospital and once by a visiting home nurse between 3 and 8 days of life.

Results showed that 48 newborns (6 percent) developed serious hyperbilirubinemia. The predictive ability of the predischarge measurement and the assessment of additional risk factors were similar. But when gestational age was added to the list of risk factors and combined with the predischarge measurement, the predictive ability improved significantly. Seventy percent of the babies were categorized as low risk, 17 percent were in the middle, and 13 percent were in the high risk category.

The authors concluded that the most accurate method for identifying those newborns at risk for severe hyperbilirubinemia was to combine a predischarge bilirubin measurement with the baby’s gestational age. The results of the study can be found in the 16 January 2008 issue of Pediatrics.

“We found that by measuring the bilirubin in every baby, and combining that information with the baby’s gestational age, you could accurately predict which infants are at very high risk and which ones are at very low risk,” said Keren.

“It did a nice job of pulling out a very large group of babies you don’t have to worry about and a small group of babies that need to be followed closely,” added Keren.

Keren cited as limitations, the small sample size, and the fact that half of the babies were black, acknowledging that black infants are less likely to develop hyperbilirubinemia. He cautioned that more research is needed to assess the cost effectiveness of a universal program and whether it reduces the incidence of severe hyperbilirubinemia.