Despite a heavy emphasis on expanded screening for autism, a new study suggests that little is known about whether such efforts are leading to earlier diagnosis and treatment.

In a new review, researchers found that routine screening for autism has increased the number of kids flagged as possibly having the developmental disorder, but it remains unclear whether or not children go on to receive further evaluation.

“We found a considerable lack of follow-up on what happens to children who score at high risk for developing autism,” said Amy Daniels, assistant director for public health research at Autism Speaks and the lead author of the study published in the February issue of the Journal of the American Academy of Child and Adolescent Psychiatry.

For the review, researchers looked at 40 studies published between 1990 and 2013 examining the effectiveness of 35 different approaches for screening young children for autism.

They found that few studies addressed whether or not children determined to be at high risk for autism went on to receive a diagnosis or treatment. And among the studies that did look at how kids fared after screening, researchers found that some children were not receiving continued care or referrals to specialists even after being flagged as at risk.

“We need to know why,” Daniels said. “Are pediatricians advising parents to take a wait-and-see approach? If so, that’s a concern because the sooner children get treatment, the better their outcomes.”

Though autism can be reliably diagnosed at age 2, most children are not diagnosed until after age 4, according to the U.S. Centers for Disease Control and Prevention.

The American Academy of Pediatrics recommends that all children be screened for autism at 18 and 24 months and health insurers are required to cover the assessments at no cost under the Affordable Care Act.

Researchers behind the new study emphasized that screening is just the first step and is only effective if it leads to kids receiving appropriate services. They said further efforts are needed to ensure that children found to be at risk have access to a full diagnostic evaluation and early intervention as needed.

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