Sensitivity and Specificity Between the Screening Tool for Autism in Toddlers and Young Children (STAT) and Autism Diagnostic Observation Schedule (ADOS-2).

The current study evaluated the agreement of the Screening Tool for Autism in Toddlers & Young Children (STAT) in differential diagnosis of autism in an outpatient clinical population, compared to the more time and resource-intensive Autism Diagnostic Observation Schedule-Second Edition (ADOS-2). Sensitivity and specificity comparative analyses were completed on 44 patients (aged 24-36 months) who were administered both the STAT and the ADOS. Sensitivity and specificity were also calculated independently on patients that received a STAT (n = 102, 24-36 months) or ADOS-2 (n = 72, 24-36 months) and multidisciplinary clinical evaluation. Using clinical diagnosis as the measure of truth, 33 of the 44 received a clinical diagnosis of ASD. Agreement between the STAT and ADOS-2 was 90.9% (40/44; 95% CI 78.3-97.5%). The sensitivity of the STAT was 90.9% (30/33; 95% CI 75.7-98.1%) and the sensitivity of the ADOS was 100% (33/33, 95% CI 89.4-100%) in our sample. The specificity of the STAT was 90.9% (10/11; 95% CI 58.7-99.8%) and the specificity of the ADOS was 100% (11/11; 95% CI 75.1-100.0%). The STAT showed high sensitivity and moderate specificity in differentiating children with autism from those with other neurodevelopmental disorders in this outpatient clinic population. There was excellent agreement between the STAT and ADOS-2. The STAT may be an acceptable diagnostic tool to refine clinic models and reduce wait times for evaluation in toddlers who present with concerns for autism.