Autism Spectrum Disorder in Young Children: Screening -- Children aged 18 to 30 months


Grade: I The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.

Specific Recommendations

The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for autism spectrum disorder (ASD) in young children for whom no concerns of ASD have been raised by their parents or a clinician.

Frequency of Service

No information available.

Risk Factor Information

Although a number of potential risk factors for ASD have been identified, there is insufficient evidence to determine if certain risk factors modify the performance characteristics of ASD screening tests, such as the age at which screening is performed or other characteristics of the child or family.


Clinical Considerations

Patient Population Under Consideration

This recommendation applies to children who have not been diagnosed with ASD or developmental delay and for whom no concerns of ASD have been raised by parents, other caregivers, or health care professionals.

Screening Tests

A number of tests are available for screening for ASD in children younger than 30 months. The most commonly studied tool is the Modified Checklist for Autism in Toddlers (M-CHAT) and its subsequent revisions (Modified Checklist for Autism in Toddlers With Follow-Up [M-CHAT-F] and Modified Checklist for Autism in Toddlers–Revised, With Follow-Up [M-CHAT-R/F]). The M-CHAT-R/F is a parent-rated scale, and a positive finding leads to a follow-up interview. If the follow-up interview is positive, a full diagnostic workup for ASD is indicated. The screening process assesses communication skills, joint attention, repetitive movement, and pretend play.

Treatments and Interventions

Treatments for ASD include behavioral, medical, educational, speech/language, and occupational therapy and complementary and alternative medicine approaches. Treatments for young children in the target age group for routine screening for ASD are primarily behavioral interventions, particularly early intensive behavioral and developmental interventions, which may include approaches incorporating applied behavior analysis principles, parent training components, and play- or interaction-based interventions. Among the behavioral interventions, those based on applied behavior analysis have the highest-quality data supporting their effects on cognitive and language outcomes. These interventions can be delivered in a home or school setting and are generally time-intensive, with some programs requiring up to 40 hours a week.2

Suggestions for Practice Regarding the I Statement

Potential Preventable Burden

Autism spectrum disorder can cause significant social, communication, and behavioral challenges for affected children and place substantial strain on family members and other caregivers. Treatment and maturation may reduce the effects of the core symptoms of ASD for some children, but others may experience long-term effects on education, employment, and ability to live independently.2 It is important that clinicians listen carefully to parents when concerns are raised by the parents or during an examination and make prompt use of validated tools to assess the need for further diagnostic testing and services. Disparities have been observed in the frequency and age at which ASD is diagnosed among children by race/ethnicity, socioeconomic status, and language of origin, creating concern that certain groups of children with ASD may be systematically underdiagnosed.3 It is important to note that an "I" statement is not a recommendation for or against screening. In the absence of evidence about the balance of benefits and harms, clinicians should use their clinical judgment to decide if screening in children without overt signs and symptoms is appropriate for the population in their care.

Potential Harms

Although there is limited evidence about the harms of screening for ASD in children, reported potential harms include misdiagnosis and the anxiety associated with further testing after a positive screening result, particularly if confirmatory testing is delayed because of resource limitations. Behavioral treatments are not generally thought to be associated with significant harms but can place a large time and financial burden on the family. Other treatments for ASD are less well studied and were not included in this review.

Current Practice

A 2004 survey of pediatricians in Maryland and Delaware found that 8% screened specifically for ASD. Few data are available regarding the current prevalence of screening for ASD by clinicians in the United States.4 More recent surveys have found higher rates, although they remain less than 60%.5-8

Useful Resources

The Centers for Disease Control and Prevention provides web-based continuing education for clinicians called Autism Case Training (available at, as well as other information about ASD for families (available at

The Health Resources and Services Administration’s web site provides links to training resources for professionals (available at

The M-CHAT screening tool is available online for free at Other professional and advocacy organizations have also developed toolkits and resources.

The USPSTF has made a recommendation on screening for speech and language delays and disorders among children 5 years or younger (available at

Other Considerations

Research Needs and Gaps

Research has focused on screening and diagnostic tools and treatment for symptomatic children, especially those who are severely affected. Good-quality studies are needed to better understand the intermediate and long-term health outcomes of screening for ASD among children without obvious signs and symptoms and whether earlier identification through universal screening is associated with clinically important improvements in health outcomes. These studies are especially needed in populations with low socioeconomic status and minority populations, where access to care may be more limited. A number of different study designs could greatly improve the understanding of the potential of screening. Large, good-quality, randomized clinical trials (RCTs) of treatment that enroll young children with ASD identified through screening and that report patient-centered outcomes are critical to understanding the effects of screening. Treatment could be compared with a wait-list control, less intense treatment, or an alternative treatment, as in the trials reviewed by the USPSTF. Similar studies in children identified through screening have recently begun to be published, indicating that this is a feasible approach.9, 10 Pragmatic quasi-experimental designs, such as stepped-wedge trials, in regions with low screening rates could compare the effects of screening at 18 and 24 months with later screening or case-finding on educational, behavioral, functional, and IQ measures at 6 years. Randomized clinical trials of screening may be feasible in locations where screening is not standard practice or recommended. Studies following up large samples of screen-negative children, although resource-intensive, would provide valuable information regarding screening specificity.




Autism spectrum disorder is a developmental disorder characterized by persistent and significant impairments in social interaction and communication and restrictive and repetitive behaviors and activities, when these symptoms cannot be accounted for by another condition. In 2010, the prevalence of ASD in the United States was estimated at 14.7 cases per 1000 children, or 1 in 68 children, with substantial variability in estimates by region, sex, and race/ethnicity.1


The USPSTF found adequate evidence that currently available screening tests can detect ASD among children aged 18 to 30 months.

Benefits of Early Detection and Intervention or Treatment

The USPSTF found inadequate direct evidence on the benefits of screening for ASD in toddlers and preschool-age children for whom no concerns of ASD have been raised by family members, other caregivers, or health care professionals. There are no studies that focus on the clinical outcomes of children identified with ASD through screening. Although there are studies suggesting treatment benefit in older children identified through family, clinician, or teacher concerns, the USPSTF found inadequate evidence on the efficacy of treatment of cases of ASD detected through screening or among very young children. Treatment studies were generally very small, few were randomized trials, most included children who were older than would be identified through screening, and all were in clinically referred rather than screen-detected patients.

Harms of Early Detection and Intervention or Treatment

The USPSTF found that the harms of screening for ASD and subsequent interventions are likely to be small based on evidence about the prevalence, accuracy of screening, and likelihood of minimal harms from behavioral interventions.

USPSTF Assessment

The USPSTF concludes that there is insufficient evidence to assess the balance of benefits and harms of screening for ASD in children aged 18 to 30 months for whom no concerns of ASD have been raised. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.


Recommendations of OthersThe American Academy of Pediatrics’ Bright Futures guidelines recommend universal screening for ASD in all children at ages 18 and 24 months in addition to developmental surveillance and monitoring.17, 18 The American Academy of Family Physicians concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for ASD in children for whom no concerns of ASD have been raised by their parents or clinical provider.19 The American Academy of Neurology and the Child Neurology Society recommend routine developmental surveillance be performed on all children to identify those at risk for any type of atypical development, followed by screening specifically for autism using one of the validated instruments (the M-CHAT or Autism Screening Questionnaire).20 The American Academy of Child and Adolescent Psychiatry recommends that the developmental assessment of young children and the psychiatric assessment of all children should routinely include questions about ASD symptomatology.21 The UK National Screening Committee does not recommend systematic population screening, citing concerns about the stability of ASD diagnosis at a young age, lack of data on positive predictive value, and weakness of the evidence for the efficacy of treatment.22


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