Autism testing, rewritten: what changed and why

This site promises that when a figure moves, the page changes and the blog keeps the record. Today a lot moved at once, so this post is longer than usual.

What is new

Parents searching for “autism testing” are usually asking two different questions, and we had one page trying to answer both. Now there are seven.

• Autism genetic testing: what it finds, what it costs, and what to ask — the rewritten main guide. What each test reads, how often testing finds something (with the study named for every figure), what a result can and cannot change, cost, and how to get tested.
• Autism testing explained — the other question: how a child gets evaluated. Screening, the diagnostic evaluation, the medical tests that follow, and the free routes through early intervention and the school district.
• Chromosomal microarray (CMA) for autism — what the most common first test finds and what it misses.
• Fragile X testing after an autism diagnosis — why it needs its own test, who is offered it, and what a premutation means for the family.
• Autism genetic testing cost and insurance — the honest range, what insurers ask for, Medicaid, appeals, and the no-cost research routes.
• Autism genetic testing results explained — positive, negative and uncertain results, secondary findings, and what a variant of uncertain significance is not.
• Is there a blood test for autism? — no, and what a lab can actually tell you.

The whole exome sequencing guide stays as it was, with the corrections below. Every city page’s diagnosis listings are now titled for what parents search — autism testing and diagnosis in that city — and link the evaluation guide.

What was corrected

“Five times the yield.” Our WES page and every city and state page said whole exome sequencing finds a cause “roughly five times” as often as a chromosomal microarray. That comparison places figures from different studies of different children side by side, and it circulates mainly in laboratory marketing. In the one study that ran both tests on the same children, a microarray found a cause in 9.3% and exome sequencing in 8.4% — comparable, in the authors’ own word (Tammimies and colleagues, JAMA, 2015). Across studies, microarray yield in autism runs from about 3% to about 9% depending on who was tested. The pages now say that.

The secondary-findings list. Three pages said the professional list of genes reported as secondary findings had 81 genes. That was the 2023 version; the list was updated in 2025 and now has 84. Corrected everywhere it appeared.

A broken link. Every city guide linked an evaluation page at an address that did not exist. Fixed.

How the new pages were checked

Every number on the seven pages names its study, and every study was read at the abstract before it was cited. Each page then went through a separate claim-by-claim review against those abstracts and, where the abstract was not enough, the full text. That review changed about seventy sentences before publication — among them a claim about a lab’s pricing that its own site does not make, a cost figure that would have read as a price when it was not one, and a statement about how Fragile X premutations are inherited that had the two parents the wrong way round. None of those reached the site.

We would rather tell you that than pretend the first draft was right.

What to do with this

If your child has an autism diagnosis and nobody has mentioned genetic testing, start here and take the questions at the end to your next appointment. If you are still trying to get an evaluation, start here instead. If you find a figure that does not match its study, write to us; the page will change, and this blog will say so.