A new rapid way to decode the DNA of sick newborns may help doctors diagnose genetic diseases faster in their tiniest patients -- in roughly two days instead of weeks.

Gene-mapping currently takes so long, and is so expensive, that it's not part of routine medical care. But researchers at Children's Mercy Hospital in Kansas City, Mo., say a speedier method could shorten the anguished wait for a diagnosis for some newborns in intensive care.

They combined a faster gene-analyzing machine with a computer program that uses a baby's symptoms to zero in on the most likely culprit.

Wednesday, they reported using the faster test to help diagnose a handful of babies, and plan to begin more routine gene mapping of sick newborns by year's end.