A revamped screening tool that relies on parents answering just 20 questions is far more accurate than previous assessments at helping flag young kids at risk for autism, researchers say.

With the updated questionnaire, doctors identified fewer children at risk for autism, but more of those who were spotted in the test were ultimately diagnosed with the developmental disorder as compared to earlier screening tools, according to findings published late last month in the journal Pediatrics.

“This checklist can more accurately identify children likely to have autism so they can get the treatment and support they need,” said Alice Kau of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, which funded the study. “Given that the typical autism diagnosis occurs at age 4, it also offers the possibility of detecting autism much earlier.”

That’s significant, Kau said, since research shows that earlier intervention generally leads to better outcomes.

The study looked at an updated version of an existing screening method. The revised assessment — known as the Modified Checklist for Autism in Toddlers, Revised with Follow-Up, or M-CHAT–R/F — is designed for pediatricians to administer during regular well-child visits at ages 16 to 30 months.

Based on parent responses, the screening allows doctors to identify a child as having a low, medium or high risk for autism. Those considered to be at risk are then referred for additional questioning or for an evaluation.

Researchers looked at more than 16,000 children who were evaluated using the updated screening. Ultimately, 93 percent were determined to be at low risk for autism while 6 percent were considered to have medium risk and 1 percent were at high risk.

Of those in the medium or high range, 95 percent were later diagnosed with some type of developmental delay and more than 47 percent had autism, the study found.

The revised assessment — which is also available online — features more examples, rephrased questions and does away with other questions that did not garner significant response in an earlier version.

“Earlier tools cast a wider net, but these refinements will allow health care providers to focus energy where it is needed most and will reduce the number of families who go through additional testing but which ultimately do not need treatment interventions,” said Deborah Fein of the University of Connecticut, a senior author of the study.