There is a debate about whether the test should be introduced in the UK
Routine screening of newborn babies for a life-threatening heart problem can save lives, a Swedish study has found.
Researchers found checking blood oxygen levels increased detection of a congenital heart defect which affects up to two in a thousand babies.
The British Medical Journal online study says just under a third currently leave hospital undiagnosed, leading to added complications and more deaths.
UK experts are investigating if screening should be introduced.
In affected babies, a blood vessel called the ductus arteriosus - which bypasses the baby's non-functioning lungs when in the uterus and normally closes off soon after birth - remains partly open.
Experts are seeking better ways of detecting such defects as soon as possible after birth.
Babies can display symptoms such as a heart murmur, look "blue", be breathless or be unable to feed.
But others do not show any signs of illness, and so defects can be missed until the baby's condition deteriorates because their heart cannot cope.
And the researchers suggest that as the time mothers stay in hospital with their newborn babies is reduced, the number leaving hospital with the duct malformation is likely to increase.
The pulse oximetry screening technique uses light sensors on the hand and foot to measure the concentration of oxygen in the blood. The non-invasive takes just a few minutes to complete and has a low rate of false-positive results.
A low concentration of oxygen can be a sign there is a heart problem and that further tests are needed.
The researchers screened all 39,800 babies born in the West Gotaland region of Sweden between July 2004 and March 2007 using pulse oximetry before a physical examination was carried out.
Sixty babies were found to have the disorder.
The accuracy of their results was compared with other Swedish regions where only physical checks were used, where 100 children were diagnosed.
The combination of pulse oximetry screening and physical checks detected 92% of duct-dependent heart disease cases, compared with 72% picked up through physical checks alone.
No babies died in West Gotaland from undiagnosed heart disease, while there were five deaths in the other regions.
Writing in the BMJ study, the researchers led by Professor Ingegerd Ostman-Smith of Gothenburg University, said: "Such screening seems cost neutral in the short term, but the probable prevention of neurological morbidity and reduced need for preoperative neonatal intensive care suggest that such screening will be cost effective long term."
In an editorial in the same journal, Professor Keith Barrington from Canada's University of Montreal said the study suggested pulse oximetry was a low risk and low cost strategy for improving the detection of critical congenital heart disease.
He added: "Serious consideration should be given to its introduction wherever neonatal cardiac surgery is available."
Cathy Ross, of the British Heart Foundation said: "At the moment there are only a limited number of hospitals that would be able to carry out the necessary specialised echocardiograms required to confirm a diagnosis.
"Careful consideration will be needed as to how these practical and logistical problems can be overcome before this is widely offered in the NHS."