Early and Repeated Screening Detects Autism Spectrum Disorder

Abstract

To evaluate timing and accuracy of early and repeated screening for autism spectrum disorder (ASD) during well-child visits. Using a longitudinal study design, toddlers (n=5784) were initially screened at 12 (n=1504), 15 (n=1228), or 18 (n=3052) months during well-child visits, and rescreened at 18, 24, and 36months. Of those screened, 368 toddlers attended an ASD evaluation after a positive screen and/or a provider concern for ASD at any visit. Screens initiated at 12months yielded an ASD diagnosis significantly earlier than at 15months (P=.003, d=0.99) and 18months (P<.001, d=0.97). Cross-group overall sensitivity of the initial screen was .715 and specificity was .959. Repeat screening improves sensitivity (82.1%), without notably decreasing specificity (all >93.5%). Screening at 18months resulted in significantly higher positive predictive value than at 12months (X2 (1, n = 221)=9.87, P=.002, OR=2.60) and 15months (X2 (1, n=208)=14.57, P<.001, OR=3.67). With repeat screening, positive predictive value increased for all screen groups, but the increase was not significant. Screening as early as 12months effectively identifies many children at risk for ASD. Children screened at 12months receive a diagnosis of ASD significantly earlier than peers who are first screened at later ages, facilitating earlier intervention. However, as the sensitivity is lower for a single screen, screening needs to be repeated.