"We don't have research evidence to show how well screening works and whether we do more good than harm," Dr. Jan Willem Gorter, a pediatrician at McMaster University in Hamilton, Canada, told Reuters Health.

While many screening tests exist -- usually based on simple questions about the child's use of eye contact and gestures -- none of them are very accurate, Gorter and colleagues report in the journal Pediatrics.

Often the tests will misdiagnose healthy kids, such as one recent test that yielded false positives a quarter of the time, or they will fail to detect autism.

"The potential burdens on families of r

It's estimated that autism spectrum disorders, which range from mild Asperger's Syndrome to severe mental retardation and social disability, affect nearly one percent of kids in the U.S., putting a significant burden on families and society at large.

Both the American Academy of Pediatrics and the U.S. Centers for Disease Control and Prevention encourage routine screening for the disorders.

But the new report, a review of the medical literature, suggests those recommendations are premature.

"We don't have research evidence to show how well screening works and whether we do more good than harm," Dr. Jan Willem Gorter, a pediatrician at McMaster University in Hamilton, Canada, told Reuters Health.

While many screening tests exist -- usually based on simple questions about the child's use of eye contact and gestures -- none of them are very accurate, Gorter and colleagues report in the journal Pediatrics.

Often the tests will misdiagnose healthy kids, such as one recent test that yielded false positives a quarter of the time, or they will fail to detect autism.

"The potential burdens on families of receiving a misdiagnosis (either a false-positive or a false-negative) may be enormous," the researchers write, "and there might be labeling effects that can be hard to remove."

They found other reasons to avoid screening, too.

For instance, there is no cure for autism, and interventions to help the kids function better on a daily basis often have shaky underpinnings and cost a lot.