Primary Care Autism Screening and Later Autism Diagnosis
OBJECTIVES: To describe the proportion of children screened by the Modified Checklist for abstract
Autism in Toddlers (M-CHAT), identify characteristics associated with screen completion, and
examine associations between autism spectrum disorder (ASD) screening and later ASD
diagnosis.
METHODS: We examined data from children attending 18- and 24-month visits between 2013
and 2016 from 20 clinics within a health care system for evidence of screening with the
M-CHAT and subsequent coding of ASD diagnosis at age .4.75 years. We interviewed
providers for information about usual methods of M-CHAT scoring and ASD referral.
RESULTS: Of 36 233 toddlers, 73% were screened and 1.4% were later diagnosed with ASD.
Hispanic children were less likely to be screened (adjusted prevalence ratio [APR]: 0.95, 95%
confidence interval [CI]: 0.92–0.98), and family physicians were less likely to screen (APR:
0.12, 95% CI: 0.09–0.15). Compared with unscreened children, screen-positive children were
more likely to be diagnosed with ASD (APR: 10.3, 95% CI: 7.6–14.1) and were diagnosed
younger (38.5 vs 48.5 months, P , .001). The M-CHAT’s sensitivity for ASD diagnosis was
33.1%, and the positive predictive value was 17.8%. Providers routinely omitted the M-CHAT
follow-up interview and had uneven referral patterns.
CONCLUSIONS: A majority of children were screened for ASD, but disparities exist among those
screened. Benefits for screen-positive children are improved detection and younger age of
diagnosis. Performance of the M-CHAT can be improved in real-world health care settings by
administering screens with fidelity and facilitating timely ASD evaluations for screen-positive
children. Providers should continue to monitor for signs of ASD in screen-negative children.