ADOS-2 Test : What the Autism Assessment Tool Is and How It Works

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A trained clinician sets up short activities and watches how a person communicates, plays and interacts. A short explainer with music and captions. 52 seconds. Watch it full screen · See all short explainers

The ADOS-2 is a standardized observation. A trained clinician sets up short activities and watches how a person communicates, plays and interacts. The publisher describes it as a semi-structured tool that covers communication, social interaction, play, and restricted and repetitive behaviours. ADOS II is another way to write ADOS-2. The ADOS-2 is the revised edition of the original ADOS.

It is not a written quiz, and there is nothing for a child to study. It is not a pass or fail test either. The Canadian Paediatric Society (CPS) says findings from a diagnostic tool cannot be used alone to diagnose autism. They should add to the clinician’s judgment and the DSM-5 criteria.

The publisher says the ADOS-2 is viewed as the gold standard for observing autism. That is the publisher’s own description. Not every Ontario assessment uses it. Health Sciences North says its Sudbury hub reserves in-depth ADOS-2 testing for complex cases only, so ask your assessor which tools they plan to use and why.

The ADOS-2 has five modules. A person is given one module, chosen by expressive language level and age. The publisher lists ages from 12 months to adulthood.

A session is one-on-one with a clinician. The publisher says each module takes 40 to 60 minutes to give. The full assessment is longer, because the clinician also gathers history and talks with you.

The clinician records the behaviours seen in the session, then uses a scoring form for that module. For Modules 1 to 4, the publisher says scores are compared with cutoffs and placed in one of three groups: autism, autism spectrum or non-spectrum. The Toddler Module gives ranges of concern instead, which the publisher says avoids a formal label at a very young age.

Parents cannot score it at home. The publisher lists qualification level C as required. For that reason this site does not publish score sheets or scoring charts. A score on its own does not name a diagnosis. The clinician reads it with your child’s history, the parent interview and other findings.

These three names come up often and are easy to mix up. The ADOS-2 is an observation of the child. The ADI-R is an interview with a parent or caregiver. The M-CHAT-R/F is a screening questionnaire, not a diagnostic tool.

Some assessments use both the ADOS-2 and the ADI-R, and some use neither. CPS notes that some jurisdictions require both to inform a diagnosis. In Ontario, ask your assessor what they use.

Yes. The publisher lists ages from 12 months to adulthood, and Module 4 is for verbally fluent older adolescents and adults. Whether an adult assessor uses it is up to that assessor. Routes, fees and waits for adults differ from the children’s diagnostic hubs, and this page lists no adult services.

Ontario lists doctors, psychologists, psychological associates and nurse practitioners among the professionals who can diagnose autism. Our answer on who can diagnose autism has the full list. To find an assessor, start with the five diagnostic hubs on ontario.ca or ask your child’s doctor. This site does not rank assessors.

When you book, ask directly: "Do you use the ADOS-2, and which module?" A clear answer sounds like "Yes, Module 2, because of your child’s age and language level." A vague answer such as "we use standardized tools" deserves a follow-up question.

ADOS-2 results alone do not make a diagnosis. A qualified diagnostician reads them with other information and issues a written diagnosis. That written diagnosis, not the ADOS-2 score sheet, is what you use to register with AccessOAP.

Ontario lists four items the written diagnosis must contain. The full checklist is on our page about what an autism assessment includes. Naming the tool used is optional. ontario.ca lists the type of diagnostic screening tool used among the details a professional may add, and says those details are not required to apply.

The ADOS-2 is one part of an assessment, so a clinic may quote one fee for the whole assessment instead of pricing the tool alone. Ask for an itemised written quote that names the tools, the report and any feedback meeting.

Hospital hubs are a different case. Holland Bloorview says initial assessments at its Toronto hub are covered by OHIP, so families are not charged. Private clinics set their own fees. This page gives no dollar amounts because fees differ by clinic.

Each stage of an autism assessment has its own guide on this site.

Is the ADOS-2 covered by OHIP?

It depends on who gives the assessment and where. Holland Bloorview says initial assessments at its Toronto hub are covered by OHIP, so families are not charged. A private clinic sets its own fee. Ask each service in writing what it covers. Our OHIP answer explains more.

Can the ADOS-2 be wrong?

No single test is always right. The publisher reports strong predictive validity, but CPS says tool findings cannot be used alone and must add to a clinician’s judgment. CPS also says girls can camouflage traits better and are probably underdiagnosed. If you disagree with a result, ask for the reasoning and consider a second opinion.

What's the difference between ADOS-2 and M-CHAT?

M-CHAT-R is a parent-completed SCREENING questionnaire used at 18 and 24-month well-baby visits to flag children who may need further assessment. It is not a diagnostic tool. ADOS-2 is a DIAGNOSTIC observation administered by a qualified clinician. A positive M-CHAT-R/F means the child should be referred for a diagnostic evaluation.

What is the difference between the ADOS and the ADI-R?

The ADOS-2 is a clinician observing the child through play or conversation tasks. The ADI-R is a structured interview with a parent or caregiver about development and behaviour. Some assessments use both, but not all do. Each is read with other information, since CPS says tool findings cannot be used alone.

Can my child prepare for the ADOS-2?

There is no test to study for. Tell your child in simple words that they will play or talk with a new adult. Bring usual comfort items, snacks if the clinic allows them, and the records the clinic asks for. Our preparation guide has a full list.