Child-safety advocates are stepping up calls for national standards on investigating sudden infant deaths after new revelations about the tattered patchwork of state systems determining what kills more than 4,000 babies a year.

Although federal and international authorities have had guidelines for making a diagnosis of Sudden Infant Death Syndrome for many years, experts around the country say they are often skipped or only cursorily done.

Such experts have turned up the volume for national standards after a Scripps Howard News Service study of 40,000 sudden, unexplained infant deaths since 1992 showed that geography, rather than medical evidence, often determines whether babies are found to have died from SIDS, suffocation or "undetermined" causes.

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