Dyslexia Screening vs Diagnostic Assessment: What's the Difference?

Screening for dyslexia.

If a screening test has flagged your child as "at risk" of dyslexia, does that mean they have dyslexia? And if the result says they're at low risk, can dyslexia be ruled out?

The short answer to both questions is no.

Screening can be a useful first step. But screening and diagnostic assessment do different jobs, and the difference isn't always well understood by parents or by schools. In my work as a specialist assessor, I regularly meet families whose child had a low-risk screening result, and the school took no further action because of it. A screening result was treated as the final answer, when it was only ever meant to be a starting point.

What is a dyslexia screener?

A screener is a short test that looks for possible signs of dyslexia. Many are computer-based and can be run in school without a specialist assessor.

Screeners vary in what they check. Some focus on reading and spelling. Others also look at related skills, such as phonological awareness (hearing and working with the sounds in words), memory or processing speed.

Results are usually given as a level of risk, such as low, moderate or high.

The British Dyslexia Association is clear that screening tests don't provide a diagnosis; they help show whether further assessment or support may be needed.

How accurate are screeners?

No screener is 100% accurate. A study of a computer-based screener called Lucid Rapid shows why.

Researchers at the Dyslexia Association of Singapore looked at 127 children aged 6 to 12 who had taken the screener and then had a full psychological assessment, mostly within six months.

Of the 95 children the screener flagged as at risk:

• 77 (81%) were found to have dyslexia

• 18 (19%) were not

Of the 32 children rated as low risk:

• 17 were found to have dyslexia

• 15 were not

So an "at risk" result was right most of the time, but not always. And in this group, more than half of the children rated as low risk were found to have dyslexia.

That second figure needs some context. These weren't typical classes of children. They had been put forward for screening because a parent or teacher already had concerns, and three-quarters of them were found to have dyslexia. That is far more than you'd find in the general population, and the researchers cautioned against applying their findings to all schoolchildren. The study also took place in Singapore, where many children speak another language at home, and the screener has since been updated.

Even so, the message is clear. When there are already concerns about a child, a low-risk result on its own shouldn't be the end of the conversation.

This pattern isn't unique to one tool. A 2025 review of school-based screening tools found that screeners were generally better at picking up children who have dyslexia than at correctly ruling it out in children who don't.

Why might a child be flagged but not have dyslexia?

Screeners pick up difficulties with skills linked to dyslexia, but those difficulties can have other causes.

The Singapore study shows this well. Of the 18 children who were flagged but not found to have dyslexia, half had language difficulties. Others had a more general developmental delay, suspected ADHD, a suspected developmental disorder or suspected dyscalculia. Only two showed no clear difficulties.

In other words, the screener was usually picking up something real, just not always dyslexia.

So if your child isn't diagnosed with dyslexia, it doesn't mean their difficulties aren't genuine. Understanding what is going on is just as valuable, because it points towards the right support.

Can a child have dyslexia even if they're rated low risk?

Yes. This is the point I most want parents and schools to understand.

Dyslexia doesn't look the same in every child. Some children develop strategies that help them cope, and a short screener can't check every skill in depth.

In the Singapore study, the children with dyslexia who were rated as low risk scored lower on the screener's phonic decoding task, and lower on reading and spelling tests, than the low-risk children without dyslexia. However, their reading and spelling scores were still within the average range. Their difficulties were real but less obvious, and exactly the kind that are easy to miss.

For example, a child might read familiar words accurately but struggle with new ones. Another might read reasonably well while their spelling or reading speed lags behind.

The researchers themselves stressed that screening results should be interpreted alongside information from parents and teachers, so that children who need support don't slip through the net.

What if school takes no further action?

If your child has had a low-risk result but you, their teacher or your child still have concerns, it's reasonable to raise this with the school. You could:

• Ask to speak to the SENCo (special educational needs coordinator) and explain what you're seeing at home.

• Share specific examples, such as difficulty spelling familiar words, avoiding reading, slow progress despite support, or work taking much longer than expected.

• Ask what support is in place and how your child's progress will be reviewed.

• Remember that a screener is one piece of evidence, not a verdict. Schools in England are expected to identify needs through ongoing assessment and review, not a single test.

If concerns continue, a full diagnostic assessment can provide a clear, independent answer.

What happens in a full diagnostic assessment?

In the UK, a diagnostic assessment is carried out by a specialist teacher who holds a current Assessment Practising Certificate (APC), or by an HCPC-registered psychologist.

The assessment looks in detail at reading, spelling and writing, phonological skills, memory and processing speed, and underlying language and reasoning skills.

The assessor also gathers background information about your child's development and schooling, the views of parents and teachers, and how your child approaches the tasks on the day.

Importantly, the results aren't looked at one by one. The assessor considers how they fit together, whether the difficulties are persistent, and whether something other than dyslexia better explains them.

You then receive a report explaining the findings, your child's strengths and difficulties, and recommendations for support at school and at home. It's valuable whether or not dyslexia is diagnosed.

Does my child need a diagnosis to get support?

No. Schools in England are expected to identify and respond to children's needs, and support shouldn't wait for a diagnosis. If your child is struggling with reading or spelling, that should be addressed whatever a screening result says.

A diagnostic assessment can still help by explaining why your child is struggling, so support can be better targeted.

So, is screening worthwhile?

Yes. It's a quick, accessible first step when there are concerns about a child's reading or spelling. Just keep in mind what it can and can't tell you:

• An "at risk" result means it's worth looking further. It isn't a diagnosis.

• A "low risk" result doesn't rule dyslexia out, and it shouldn't be the reason for stopping if concerns continue.

In either case, a full diagnostic assessment can give you a much clearer picture.

At Lexety, diagnostic assessments look at each child's learning profile in detail. They help families understand not just whether dyslexia is present, but why their child is finding things difficult and how best to support them.

References and further reading

Brookes, G., Ng, V., Lim, B. H., Tan, W. P. & Lukito, N. (2015). The computerised-based Lucid Rapid Dyslexia Screening for the identification of children at risk of dyslexia: A Singapore study. DAS Handbook of Early Intervention 2015, pp. 119–144. Dyslexia Association of Singapore.

Bakhti, R., Fonseka, N., et al. (2025). A narrative review of school-based screening tools for dyslexia among students. Frontiers in Public Health, 13, 1654470. https://doi.org/10.3389/fpubh.2025.1654470

British Dyslexia Association. Dyslexia screening. bdadyslexia.org.uk

Department for Education & Department of Health (2015). SEND Code of Practice: 0 to 25 years.