Currently, there is no blood test that can diagnose autism. Autism Spectrum Disorder (ASD) is a neurodevelopmental difference that is diagnosed through careful observation, developmental history and standardised assessments, not through lab tests.
However, researchers are exploring biomarkers in blood, such as genetic variations, proteins or metabolic patterns, that might one day help identify autism earlier or help us understand it better. These studies are still at an early stage and are not used in clinical diagnosis.
If you think your child may be autistic, the best next step is to talk to your GP, a paediatrician or a psychologist about a developmental assessment, rather than relying on any medical or blood test.
Is There a Blood Test for Autism?
Not yet. You may see an “autism blood test” advertised online, but no blood test is currently approved or recommended to diagnose autism. Here is what blood tests can and can’t do today:
- They can’t diagnose autism. Diagnosis is based on how a child communicates, plays, interacts and experiences the world, assessed by trained professionals.
- Genetic testing is sometimes offered after a diagnosis, for example chromosomal microarray or Fragile X testing, to look for a known genetic cause or related health needs. These tests don’t diagnose autism itself.
- Doctors may order other blood tests for other reasons, such as checking iron levels or thyroid function if there are other health concerns.
- Be cautious about commercial tests that claim to detect or “explain” autism from blood, hair or stool samples. Ask your paediatrician before paying for one.
What the Research Has Found
The study below was published in 2015. Research in this area has continued since, but no blood test is yet in clinical use.
Many scientists around the world studying Autism Spectrum Disorder (ASD) are working towards an accurate, early detection test for autism. Around the same time, researchers at NEBA Health claimed to have developed a brainwave biomarker test to help doctors tell ADHD apart from other conditions with similar signs.
Researchers at the University of California San Diego School of Medicine reported on a potential blood test for autism. The scientists believed the blood test, which was at an early stage, could identify gene-expression patterns found in autistic children before signs of autism become obvious.
Could blood test help detect autism in children?
The test was designed for children aged 1 to 4 years. At the time, the study’s lead author, Eric Courchesne, argued that behavioural assessments were often not used until children were older, and he wanted to close that gap. (Today, autism can often be reliably diagnosed from around 18 to 24 months.) Earlier identification would mean earlier support for children and families, Courchesne suggested.
Courchesne explained that researchers usually look for a biomarker in the part of the body most involved. In autism that is the brain, which can’t be sampled directly, so the team looked at blood instead.
The study, published online in JAMA Psychiatry (see below), was based on samples from 215 young boys (131 of whom were autistic). The researchers grouped gene-expression patterns by their links to immune function and protein production, then compared their new blood test with a related, older test.
The result:
The new test performed better than the older one. It had an accuracy of 83 percent, compared with 75 percent for the older test. The researchers said current autism screening tools also average about 75 percent accuracy, so the blood test performed better than other behavioral and genetic screens for infants with the disorder.
“The study is an important one as it identifies biological pathways affected in autism”, said Paul Wang of Autism Speaks. “The findings reinforce the theory that inflammatory and immune pathways are involved in autism’s development, alongside disturbances in protein synthesis,” continued Dr. Wang.
Some scientists saw this as a potential milestone in Autism diagnosis, following a similar study by researchers at Clarkson University on non-invasive saliva testing for Autism.
The researchers then planned to look for a similar blood test biomarker in girls, and started a new gene-expression study with a much larger group.
For more information on the JAMA Psychiatry study, click here.
📌 MUST READ: Can Autism Eye Movement Help Diagnose Autism
Conclusion
While a blood test for autism is not yet a clinical reality, research continues. Studies from UC San Diego and others suggest that autism-related biomarkers in blood could one day make early identification faster and more accurate. However, these findings need larger, more diverse studies before they could become reliable diagnostic tools.
For now, the most reliable path is observation and a professional developmental assessment, ideally supported by early screening through trusted autism screening tools or developmental specialists. If you have concerns, you don’t need to wait for a diagnosis to start supporting your child’s communication and play at home.
I am Ash and I celebrate Neurodiversity! Growing up with an elder brother with severe Autism was tough – but it has also taught me essential life lessons. I don’t believe that people with Autism are necessarily or have any disorder (except in extreme cases). They are just different! And that is something to be proud of! I am passionate about helping other families who may have Autism conditions in their family. So please reach out and drop me a note. I will be glad to help 🙂
