By: 3 July 2012

Newborn screening for life-threatening congenital heart defects using pulse oximetry, a simple, low-cost test that measures blood oxygen levels, is more accurate than other detection methods and should be adopted internationally as part of the routine assessment of all newborns, suggests a new meta-analysis published in The Lancet.

“The findings of this meta-analysis provide compelling evidence for introduction of pulse oximetry as a screening method in clinical practice. The sensitivity of the test is higher than present strategies based on antenatal screening and clinical examination, and the false-positive rate is very low, especially when done after 24 hours of birth”, explains Shakila Thangaratinam from Queen Mary, University of London, lead author of the study.

Congenital heart disease is responsible for more neonatal deaths than any other birth defect, but outcomes can be improved if defects are identified early.

Previous research has reported the potential of pulse oximetry to detect significant or life-threatening heart defects that might otherwise go unnoticed in well-appearing babies. But, uncertainty remains about false-positive rates and the test’s accuracy. The USA is the only country so far to adopt routine pulse oximetry screening.

Here, the researchers analysed 13 studies including data for nearly 230,000 newborn babies (doubling the numbers used in previous reviews) to assess the test’s ability to detect congenital heart disease.

Overall, they found that pulse oximetry had high specificity (99.9%) with moderate sensitivity, detecting 76.5% cases of congenital heart defects with a low false positive rate (0.14%). 

The findings also suggest that the false-positive rate was significantly lower when pulse oximetry was done after 24h (0.05%) than when it was done before 24h (0.50%). The authors say: “This finding needs to be balanced against the increasing tendency of many countries to discharge babies earlier than 24 hours and the risk of babies with serious conditions deteriorating before screening has taken place.”

They add: “In view of the many babies that have now been tested with pulse oximetry, further research in this area is unlikely to produce substantially different findings.”

They conclude: “Strong evidence exists for health-care systems to consider introduction of pulse oximetry as a screening test for critical congenital heart defects in asymptomatic newborn babies.”