Autism Diagnosis Tests: How Autism Is Diagnosed Around the World

There is no single medical test for autism. Autism diagnosis tests are really a set of tools: trained clinicians combine a detailed developmental history, careful observation, and standardized interviews or checklists, then decide whether a child meets the DSM-5-TR or ICD-11 criteria. Blood tests and brain scans cannot diagnose autism today [1][4][5].

How autism diagnosis tests and assessments work

The CDC explains that there is no medical test, such as a blood test, to diagnose autism. Doctors look at a child’s developmental history and behavior instead [1]. Clinicians compare what they find with one of two international rulebooks:

• DSM-5-TR, published by the American Psychiatric Association in March 2022 and used widely in the United States and many other countries [2]. See our guide to the DSM-5-TR autism criteria.
• ICD-11, the World Health Organization’s classification (autism spectrum disorder is code 6A02), which describes autism as a spectrum and is used by health systems around the world [3].

The AAP notes that autism can be diagnosed as young as 18 months [4]. A good assessment usually includes your concerns, a developmental and medical history, a physical examination, observation of your child, and checks for other conditions that can look similar or occur alongside autism. It should also describe your child’s strengths and needs, not just give a label [5].

Autism diagnosis tests used worldwide

Most autism diagnosis tests fall into two groups: diagnostic tools used by specialists, and shorter screening tools that show who needs a full assessment. A Cochrane review found that all of the main diagnostic tools varied in accuracy, and none was accurate enough to be used as the only test [6]. NICE in the UK says clinicians should not rely on any autism-specific tool alone [5].

Diagnostic tools

How accurate are these autism diagnosis tests? In the Cochrane review of preschool children, the ADOS was the most sensitive tool, with a summary sensitivity of 94% and specificity of 80%. CARS had a sensitivity of 80% and specificity of 88%, and the ADI-R was less sensitive. Accuracy was lower in better-quality studies [6]. You can read more in our guide to the ADOS-2 autism test.

Screening tools

Screening tools are not autism diagnosis tests. They are quick checklists that show which children should have a full assessment.

• M-CHAT-R/F: a 20-question parent checklist for toddlers aged 16 to 30 months, with a follow-up interview if the score is raised [13]. In a study of more than 16,000 toddlers, about half of the children who screened positive after follow-up were later diagnosed with autism, and nearly all had some developmental concern [14]. See our M-CHAT guide.
• Q-CHAT: a 25-item parent questionnaire for toddlers aged about 18 to 24 months, scored on a scale rather than yes or no [15]. A shorter 10-item version has been compared with the M-CHAT at 18 months [16].
• SCQ: a 40-item yes-or-no questionnaire completed by a parent, for ages 4 and up with a mental age over 2 years [17].
• ASQ-3: a general developmental screener for children from 1 month to 5 and a half years [18]. It is not autism-specific, but it can pick up delays that lead to an autism assessment.

FDA-authorized diagnostic aids

Three devices are now authorized by the US Food and Drug Administration to help clinicians diagnose autism in children. These newer autism diagnosis tests are aids. They are designed to support, not replace, a clinician’s assessment.

The newest, cleared in October 2026, is Neurora, AI software that analyses video and audio recorded during a clinician’s behavioural assessment of children aged 18 months to 12 years. Like the others, it supports a clinician’s judgment rather than replacing it [40].

Canvas Dx (Cognoa)

In June 2021, the FDA authorized the first machine learning-based autism diagnosis aid for children aged 18 months through 5 years with developmental concerns. It combines a parent questionnaire, short home videos reviewed by trained analysts, and a questionnaire completed by the child’s health care provider [19]. In the main study of 425 children, the device gave a definite answer for only about a third of children (32%). When it did, it matched specialists’ conclusions well, with a sensitivity of 98% and a specificity of 79% [19][20]. A 2025 clearance under the name Canvas Dx lists ages 18 through 72 months and states again that it is not a stand-alone diagnostic [21].

EarliPoint (EarliTec Diagnostics)

EarliPoint uses eye-tracking while a child watches short videos of social scenes. It was first cleared in June 2022 for children aged 16 to 30 months, for use in specialized developmental centers [22]. In its main study of 475 toddlers, sensitivity was 71% and specificity was 81% compared with expert diagnosis, with better results when experts were certain of the diagnosis [23]. A 2025 clearance removed the specialized-center wording [24], and in March 2026 the FDA cleared a newer version, the EarliPoint Assessment, for children aged 16 months through 7 years [25].

What they cannot do: none of these devices is a stand-alone test, none works for every child, and all are available only through health care providers. Many families will never be offered one, and that is fine. A skilled clinician can diagnose autism without them. For more on lab tests, scans, and apps, see is there a medical test for autism?

Medical tests a doctor may order alongside

Medical tests are not autism diagnosis tests, but your child’s doctor may suggest some to look for causes, rule out other problems, or check related health needs.

• Hearing and vision: hearing loss can look like a communication difference, so hearing and vision results should be part of the picture [5][28].
• Genetic testing: a summary of the AAP guidance recommends chromosomal microarray and fragile X testing for children with autism, with exome sequencing as an option if these are negative [26]. The American College of Medical Genetics and Genomics strongly recommends exome or genome sequencing as a first- or second-tier test for children with developmental delay, intellectual disability, or congenital anomalies [27]. A genetic result can explain why, but it does not decide whether a child is autistic.
• Lead and iron: blood tests may be checked if a child often eats non-food items (pica) [26].
• EEG: only if seizures are suspected. Routine EEGs are not recommended [5][26].
• MRI and other scans: NICE advises against routinely doing medical investigations as part of an autism assessment, and that includes brain scans. A doctor may order one for a specific medical reason [5].

How autism diagnosis tests are used in different countries

United States

The AAP recommends autism-specific screening for all children at 18 and 24 months, alongside ongoing developmental checks [4][1]. The US Preventive Services Task Force said in 2016 that there was not enough evidence to judge screening of children without concerns, and it is updating that review [29]. Diagnosis is usually made by trained specialists, such as developmental pediatricians or child psychologists [1]. Read more in who can diagnose autism.

United Kingdom

NICE guideline CG128 asks local autism teams to include a pediatrician or child psychiatrist, a speech and language therapist, and a psychologist, and to start the assessment within 3 months of referral to the autism team [5]. The UK does not run population screening for autism, because no test is accurate enough to screen all children [31]. Families usually start with a GP, health visitor, or school, and the NHS says an assessment can take a few months or longer [30].

Canada

The Canadian Paediatric Society describes three routes: a single trained provider for clear cases, shared care with another professional for more complex cases, and full team assessments. Tool results should inform, not replace, clinical judgment, and some jurisdictions require tools such as the ADOS and ADI-R for access to services [28].

Australia

The National Guideline, first published in 2018 and updated in 2023, was approved by the NHMRC in December 2023. It allows either a lead practitioner (with input from at least one other professional) or a consensus team, says standardized tools should be considered but not relied on alone, and uses current DSM or ICD criteria [33].

Europe and the WHO

European child psychiatrists have published practice guidance on detection and diagnosis, noting that services vary widely and are limited in many countries [34]. The WHO estimates that about 1 in 127 people were autistic in 2021 and recommends routine developmental checks in child health visits [35].

India

The INCLEN Diagnostic Tool for Autism Spectrum Disorder (INDT-ASD) was developed and validated in India for children aged 2 to 9 years [36]. Government guidelines from 2016 use INCLEN tools to identify autism and the Indian Scale for Assessment of Autism (ISAA) to measure the level of disability for official certification [37].

Gulf and Middle East

A Saudi expert consensus recommends screening with tools such as the M-CHAT and SCQ, diagnosis by an experienced multidisciplinary team using DSM-5, tools such as the ADOS-2 and CARS-2, hearing tests, and offering genetic testing to families [38]. In Qatar, one published evaluation describes a specialized multidisciplinary assessment clinic for children aged 6 to 17 within child mental health services [39].

Waiting lists, public and private options

Waiting times vary widely by country and region. Public services are usually low-cost or free but can involve long waits. Private assessments can be faster but cost money, and their quality varies. In England, NHS bodies advise asking any provider whether they follow NICE guidance, and note that a private diagnosis may not automatically lead to NHS follow-up care [32]. Wherever you live, ask who will see your child, which autism diagnosis tests they use, whether a team is involved, and what the report will include.

You do not always need to wait for a diagnosis to get help. In England, for example, schools are expected to support children based on need [32]. Ask your local services what is available while you wait. Our autism assessment guide explains what to expect on the day.

When to talk to a professional

Talk to your child’s doctor if you have any concerns about how your child communicates, plays, or relates to others, or if your child seems to lose skills they had before. Ask for a developmental screening and, if needed, a referral for a full assessment. Be cautious of any company that offers a quick, online, or lab-only autism diagnosis.

Frequently asked questions

Is there a blood test for autism?

No. The CDC states there is no medical test, such as a blood test, that can diagnose autism. Researchers are studying blood, urine, and other biological markers, but none is accurate enough for diagnosis yet. Doctors may order blood tests, such as genetic testing, to look for a cause or related health problems, not to decide whether a child is autistic.

Which of the autism diagnosis tests is most accurate?

In a Cochrane review of preschool children, the ADOS was the most sensitive tool, while CARS had slightly higher specificity (about 88% vs 80%). But no tool is accurate enough on its own. The most reliable diagnosis comes from an experienced clinician or team who combines your child’s history, observation, standardized tools, and checks for other conditions against DSM-5-TR or ICD-11 criteria.

Can autism be diagnosed with an app or online test?

Online questionnaires can help you decide whether to ask for an assessment, but they cannot diagnose autism. FDA-authorized aids, including Canvas Dx, EarliPoint and Neurora, can help clinicians diagnose children, but only as part of a clinical assessment. Be wary of websites that promise a diagnosis from a quiz, a video, or a lab sample alone.

At what age can autism be diagnosed?

The American Academy of Pediatrics says autism can be diagnosed as young as 18 months, and it recommends autism screening at 18 and 24 months. Some children are diagnosed later, especially if their signs are subtle or they mask differences. There is no age that is too late to ask for an assessment if you have concerns.

References

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Professional review: this guide is waiting for review by a qualified clinician. It was written and checked against the published sources listed above. How we check our guides.

This guide is general education, not medical advice. Always talk to your child’s doctor or care team. Last checked: October 2026.