brand logo

Am Fam Physician. 2020;101(10):630

Clinical Question

What is the accuracy of a two-step process for universal screening for autism spectrum disorder (ASD) in children ages 16 months to 26 months?

Bottom Line

Screening for ASD with the Modified Checklist for Autism in Toddlers with Follow-Up is effective in ruling out ASD in children who screen positive (negative predictive value of 98.6% at 2.2% prevalence). The initial screening identified approximately 10% of toddlers as possibly having ASD, although 94.8% of those children were excluded in the follow-up interview. The positive predictive value was only 14.6%, meaning that 85% of the children who screened positive for ASD were falsely positive. Although some groups recommend universal screening, the U.S. Preventive Services Task Force cites a lack of evidence to support the benefit of early identification. (Level of Evidence = 1b)


This study evaluated the effect of universal screening for autism in primary care at a single hospital using the Modified Checklist for Autism in Toddlers with Follow-Up. Over 4.5 years, they screened 25,999 children between the ages of 16 months and 26 months. At the first screening, almost one in 10 children screened positive (9.1%). However, in the follow-up interview almost all of those children (94.8%) were no longer considered to have ASD, and the final prevalence in the group was 2.2% by four years of age. The resulting positive predictive value was only 14.6%, with a negative predictive value of 98.6% (sensitivity of 38.8%; specificity of 94.9%). In other words, 85% of parents who have a child who initially screens positive will later be told the result was incorrect. The positive predictive value for girls was even lower (7.7%). For children correctly screened as positive, the time to diagnosis was an average of 7.45 months earlier than those who screened negative. Whether this benefit results in faster access to treatment with better results is not known.

Study design: Cohort (prospective)

Funding source: Foundation

Setting: Outpatient (primary care)

Reference: Guthrie W, Wallis K, Bennett A, et al. Accuracy of autism screening in a large pediatric network. Pediatrics. 2019;144(4):pii:e20183963.

Editor's Note: Dr. Shaughnessy is an assistant medical editor for AFP.

POEMs (patient-oriented evidence that matters) are provided by Essential Evidence Plus, a point-of-care clinical decision support system published by Wiley-Blackwell. For more information, see Copyright Wiley-Blackwell. Used with permission.

For definitions of levels of evidence used in POEMs, see

To subscribe to a free podcast of these and other POEMs that appear in AFP, search in iTunes for “POEM of the Week” or go to

This series is coordinated by Natasha J. Pyzocha, DO, contributing editor.

A collection of POEMs published in AFP is available at

Continue Reading

More in AFP

More in PubMed

Copyright © 2020 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP.  See permissions for copyright questions and/or permission requests.