New Blood Test Could Revolutionize Autism Diagnosis

Diagnosing autism spectrum disorder (ASD) is a challenging and lengthy process for physicians, largely because there is no single medical test to help. But a team of researchers has developed a blood test that can predict whether someone has ASD with up to 95% accuracy.

Their findings, published in the journal Research in Autism Spectrum Disorders in late August, show metabolites in blood can be indicators of ASD.

The current method of diagnosing the disorder “is purely observational, which makes it time-consuming,” lead study author Juergen Hahn, PhD, a professor and head of the Department of Biomedical Engineering at Rensselaer Polytechnic Institute, tells Verywell. “One result of this is while ASD can be diagnosed by 18 to 24 months, the average age of diagnosis is around four years of age. There is often a long waiting period involved between when concerns regarding ASD are noted and when an actual diagnostic observation is scheduled."

Experts think a simple blood test could be a game-changer in the field.

How Does It Work?

The test is based on an algorithm that analyzes measurements of metabolites—small molecules that are the result of a metabolic process—in a blood sample to predict whether or not a person has ASD.

The researchers analyzed how accurate the algorithm is by comparing it to data collected from children with ASD who have one or more additional conditions, like allergies or a gastrointestinal disorder.

The model was able to identify 124 of 131 participants with ASD correctly, regardless of other conditions the patient might have, meaning it’s nearly 95% accurate.

Why Does the New Test Analyze Metabolites?

Autism spectrum disorder is a developmental disorder with symptoms that generally appear in the first two years of life, according to the National Institute of Mental Health (NIMH). Scientists don’t know the exact cause of ASD, but the NIMH says that genes can act together with influences from the environment to impact development in ways that lead to ASD.

“[Metabolites] are linked to both genetics as well as environmental factors, both of which are known to play a role in autism,” Hahn says. “Also, unlike genetics, metabolites concentrations are constantly changing and can better reflect the current status of what is going on in the human body.”

Still, Hahn notes that there is no one metabolite that is indicative of ASD. Researchers have to examine a combination of several metabolites to be able to draw conclusions.

How Autism Is Currently Diagnosed

Diagnosing autism is a process. It typically starts with a developmental screening at well-child checkups. The American Academy of Pediatrics (AAP) recommends all children be screened for developmental delays at their 9-, 18-, and 24- or 30-month well-child visits and for autism, specifically, at their 18- and 24-month well-child visits.

Children who are referred for a second stage of evaluation will meet with a team of doctors that may include a:

• Developmental pediatrician
• Child psychologist
• Neuropsychologist
• Speech-language pathologist

The evaluation may look at the child’s cognitive or thinking skills, language abilities, and age-appropriate skills, the NIMH says. The child may also be given a blood test and hearing test to look for other illnesses or disorders.

The Current Path to ASD Diagnosis Isn’t Perfect

“Autism diagnosis can be a lengthy and complicated process,” Jennifer Twachtman-Bassett, MS, autism clinical specialist and program coordinator at Connecticut Children’s, tells Verywell.

It can also be difficult for medical providers to determine if a developmental delay is due to ASD or something else entirely.

“It is not uncommon that there have been concerns about a child's development from a reasonably young age, but that the actual diagnosis was only given later, after it became more apparent that the developmental delay is due to ASD,” Hahn says. “Due to these reasons, having some type of physiological test that can aid with the diagnosis process would be very helpful.”

Experts Say a Blood Test for ASD Could be a Game-Changer

Using a blood test to diagnose ASD could help patients get an official diagnosis sooner, leading to a faster start to therapy.

“Beginning services earlier could lead to better outcomes for children with autism spectrum disorder,” Twachtman-Bassett says. “Once the child is receiving treatment, the clinicians involved could more easily address any additional difficulties that develop as the child grows.”

Gina Posner, MD, a board-certified pediatrician at MemorialCare Orange Coast Medical Center in Fountain Valley, California, tells Verywell that a behavioral analysis would still likely be needed in making an autism diagnosis.

“There’s such a wide range with autism spectrum disorder,” she says. “[A blood test] makes me concerned that, immediately, a child is going to be placed into a group.”

Hahn seconds the importance of a behavioral analysis, and adds that more research is needed.

“A physiological test in conjunction with the current observational practice might be used in the future,” Hahn says. “This is still a while off, though.”