Newsweek.com

The most widely used screening tool for autism is not as accurate as hoped, according to the latest in a string of studies questioning the tests currently used to diagnose the condition.

The team at the Children's Hospital of Philadelphia network investigated the effectiveness of what is known as the Modified Checklist for Autism in Toddlers with Follow-Up (M-CHAT/F).

The checklist sees parents of toddlers fill out a 23-item electronic survey by answering "yes" or "no" questions related to the condition, including whether their child responds to their name and if they appear interested in other children. A follow-up is used to check for false positives.

The American Academy of Pediatrics recommends that all 18-to 24-month-old children are screened in this way, as diagnosing the condition as soon as possible leads to faster treatments and can improve a patient's quality of life. But the U.S. Preventive Services Task Force counters there isn't enough evidence to recommend universal screening due to limited data on the approach, including children who screen negative.

To plug the gap, the authors of the paper published in the journal Pediatricslooked at the electronic health records of 25,999 patients at Children's Hospital of Philadelphia, a network encompassing 31 pediatric primary care sites in Pennsylvania and New Jersey. The participants were aged between 16 and 26-months old when they underwent M-CHAT/F screening. The team checked the records of the children again between the ages of four and eight-years-old.

Of the total, 91 percent of children were screened using the M-CHAT/F. A total of 2.2 were diagnosed with autism at some stage. The screening picked up 38.8 percent of those who went on to be diagnosed.

The data revealed children of color, and those from low-income families, who visited practices in urban areas, used public insurance or Medicaid, and/or were exposed to a language other than English at home were more likely to miss screenings, although the rate was still at 80 percent. The researchers described this as "relatively high."

Whitney Guthrie, a clinical psychologist specializing in early diagnosis at CHOP's Center for Autism Research, stressed in a statement: "Although our findings reveal significant shortcomings in current screening tools, we want to be clear that we are not recommending that pediatricians stop universal screening.

"Instead, clinicians should continue to screen using the M-CHAT/F, while being aware that this screening tool does miss some children with ASD," he said.

Co-author Dr. Kate Wallis, a developmental pediatrician and researcher at CHOP's PolicyLab commented in a statement: "Persistent racial and economic disparities in autism screening and diagnosis are a cause for great concern, and are consistent with previous research showing that black and Hispanic children tend to be diagnosed years later than white children.

"This study revealed important limitations and provides us with new knowledge that we can use to make critical improvements to autism screening tools and screening processes, so pediatricians can properly detect and support more children with autism and reduce disparities in diagnosis and care," she said.

Autism, or Autism Spectrum Disorder, is an umbrella term for conditions where people behave and communicate in ways different to those who are neurotypical. This can encompass speech, nonverbal communication and social skills, and see them demonstrate repetitive behavior.

Autism is a spectrum disorder, meaning each individual has different strengths and challenges, according to Autism Speaks. While some can live independently and are highly skilled, others may experience severe challenges and require significant day-to-day support.

Punit Shah, an assistant professor in psychology at the U.K.'s University of Bath who did not work on the study, told Newsweek the work is "critically important" but the findings aren't particularly surprising, as it is the latest in a line of studies to show that screening measures for autism need improvement.

"This study indicates that we need to work a lot harder to develop screening tools for autism," he said.

"Its major limitation, however, is that it doesn't address the fact that we must start measuring mental processes (i.e., cognition), rather than just behaviors, to help detect and manage autism," argued Shah.

"We also need to be more upfront with parents that screening for autism is difficult, and equally remember that is a lifelong condition," he said. "So diagnostic difficulties continue into adulthood, particularly because autistic adolescents and adults often disguise their autism using psychological strategies."

Steven Stagg, senior lecturer at the U.K.'s Anglia Ruskin University, who also didn't work on the research, told Newsweek: "Current diagnostic tools for autism have been developed by observing general features of the condition of groups that have mainly consisted of white males and therefore, the diagnostic tools more readily spot autism within this group.

"The current study suggests that new diagnostic tools need to be developed from observations which include more diverse groups," he said.