How often is ME/CFS diagnosed in people who don't have it?

No personal stories, please! I'm looking for research findings on what percentage of people diagnosed with ME/CFS probably don't actually have it.

Do we know?

 

I seem to recollect an older study that suggested both false positives (diagnosed with ME/CFS when you don’t have it) and false negatives (ME/CFS diagnosis missed) were around 40% but I suspect this is unreliable. I have not found the reference again.

My reading comprehension is not up to much today, but I have found the following:

• ME Research UK - Misdiagnosis on a grand scale? https://www.meresearch.org.uk/research/other-resources/misdiagnosis-on-a-grand-scale/
• NICE - Myalgic encephalomyelitis(or encephalopathy) /chronic fatigue syndrome: diagnosis and management https://www.nice.org.uk/guidance/ng206/evidence/d-identifying-and-diagnosing-mecfs-pdf-9265183025
• NIH - Impact of Misdiagnosis in Case-Control Studies of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
  https://pmc.ncbi.nlm.nih.gov/articles/PMC9914258/
• Geraghty & Adeniji (2019) The Importance of Accurate Diagnosis of ME/CFS in Children and Adolescents: A Commentary https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2018.00435/full
  
• MEpedia - Misdiagnosis of myalgic encephalomyelitis and chronic fatigue syndrome https://me-pedia.org/wiki/Misdiagnosis_of_myalgic_encephalomyelitis_and_chronic_fatigue_syndrome

 

An old claim was about one in four. However this was entirely anecdotal I think. How would this even be calculated or recorded? We still need that diagnostic test.

 

According to what?
A lot of people are diagnosed according to old definitions or looser definitions like post viral fatigue syndromes.

What is your threshold for “don’t have it”?

 

There was a US study that found that a minority of people given a diagnosis by a doctor actually reckoned they fit criteria if I remember rightly.

I think this is another 'fact' for which there will be no precise number.

 

That's a excellent question that I haven't thought through at all. I suppose I must first define 'do have it' but even if I take current definitions, maybe that's going to vary country to country.

 

Small study from Canada

https://www.medrxiv.org/content/10.1101/2024.05.16.24307437v1
Results We included 187 participants, 45.5% (n=85) self-reported cases and 54.5% (n=102) controls; 34% (n=29) of those who self-reported ME/CFS fulfilled diagnostic criteria for ME/CFS. The population prevalence rates were 1.1% and 0.4% for self-reported and confirmed ME/CFS cases respectively. Participants displayed significantly lower scores in all eight SF-36 domains compared to the other groups. Mental component scores were similar between ME/CFS and non-ME/CFS groups. The main risk factor for low HRQoL scores was fatigue severity (β = - 0.6, p<0.001 for physical health; β = -0.7, p<0.001 for mental health).

 

I think more people are being diagnosed with ME/CFS in the last 20 years. The Canadian ME doctor I saw in the early 90s told me that he has given a dx of ME to only 10% of his patients. He based his dx on onset, history, relapses and 25 years of experience.

I personally didn't have PEM during the time I saw him.

 

I don't think we can easily know much. I do think we need to start with laying out the issues so if we find any studies we are at least contextualising them appropriately.

At this year in time the first question we need to confirm is whether we are finally confirming that the illness is 'confirmed' by 'do you have the following symptoms for x amount of time' rather than the 'rule out' confusion we had for years, which effectively made it fatigue for long enough time --> go to doctor, check it isn't iron or .. did they check anything else really? --> label as 'chronic fatigue syndrome'

Technically if we had any change to decent medicine then what we would/should be getting is those who maybe get diagnosed with something (perhaps rare) that turns out to when addressed also mean that the me/cfs 'disappears'. But we don't even know that happens because 1. comorbidities are not just likely but probably more likely than not (something makes both more likely), 2. having something else that is unaddressed could well have been a contributor to the me/cfs but sorting out that other thing doesn't then make it go away, 3. the record-keeping has been apalling.

On the other end of things we have the criteria should be focusing around eg PEM being a cardinal symptom, but also appropriately interpreted - but we eg in the UK have had fatigue and PPS clinics where we don't know what is going on and their funding seems to relate to 'each person with cfs' even though they claim as their treatments are inappropriate for me/cfs that they don't treat it, just 'cfs' or 'cfs/me'.

Which = the garbage in, garbage out weakness because the UK have been taking me/cfs funding and using it for 'anything but me/cfs' to be funded because those who don't have the illness with say and do the right things.

Having said that I suspect most of those who are diagnosed do have me/cfs, it is just the bps would love to pretend there is some huge demand of people with their imagined fiction of cfs/me from the 2000s so they can keep doing this and cutting out and harming those with me/cfs by putting them through collateral damage clinics that harm me/cfs people to 'fish out' those who don't have it and scrap-heaping us all

My point is that in any studies there will be a lot to look at very carefully because even if it is well done and insightful I don't think we can say anything is easily extrapolated.

 

Possible Racial Disparities in the Diagnosis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) (C Jones, J Younger. 2025. Int. J. Environ. Res. Public Health)

 

Do you think it's possible to answer the question, even roughly, in principle? The obvious thing to do seems to be to grab a bunch of people who have been diagnosed by a doctor and then check whether they fulfil either that country's health service criteria (which in the UK would be the NHS criteria) or maybe some international research criteria such as the IOM.

But you've said that doctors don't use research criteria when making a diagnosis and probably not health service criteria either but are using a process of pattern recognition. So if a doctor diagnoses a patient with ME/CFS according to a pattern of symptoms but that person wouldn't fit the either of those sets of criteria, can we say whether that person has ME/CFS or not? (This is all seeming a bit Schrodinger's cat.)

 

some papers mentioned here
https://www.s4me.info/threads/2025-...mments-and-articles.42305/page-17#post-583800

 

I’m wondering if you’re actually talking about two different processes here. The first one is the one where you use pattern recognition to try and figure out what you’re looking at. If you suspect ME/CFS based on e.g. PEM for months/years after a viral infection, then you move on to the second process: running through the checklist(s) to see if they fit the criteria and doing relevant tests.

For the first process, the doctor has to know A) that ME/CFS exists and B) the basics of what it looks like and common/possible triggers.

For the second, they turn to the criteria, etc. I assume this is the easy part?

Edit: I have no medical training, this is pure speculation.

 

In Austria and Switzerland, a lot of doctors don’t seem to work by outright diagnosis, but more by saying you probably have X. And then treating you as if you have X. I guess it’s a way to save time for them? But so unless they send you to another specialist or you need it for disability application, they rarely do formal diagnosis and work on instincts mostly. Of course, life threatening diseases with obvious biomedical markers like cancer and stuff are usually formally diagnosed. But things like depression and most chronic illnesses aren’t often formally diagnosed.

 

Possible overlap with neuro-sjogrens esp. with fatigue and brain fog symptoms? Some people on here report dry eyes/dry mouth symptoms.

 

I definitely have that. But then again I doubt Sjörgens could cause me to completely lose the ability to communicate or tolerate light and sounds for certain periods.

 

They don't turn to the criteria in practice, and shouldn't. Doctors should not be interested in yes or no pigeonhole medicine. They should be aware of probabilities and possibilities all the time and make judgements on management based on uncertainties.

Sticking to criteria will lead to serious clinical errors, whatever you make the criteria.

 

No, it is a way to be as safe and effective as possible. In all other walks of life we act on the basis of what is probable. It makes not sense for medicine to be different.

Acutely life threatening disease are often a situation where uncertainty is greatest. Working with probabilities is pervasive in medicine. Even with cancer confirmed by histology many decisions are based on probabilities.

 

I think we know that some doctors grossly under diagnose ME/CFS (a number do not ever diagnose it) and we know that some doctors are diagnosing it when patients do not fit criteria. How you interpret the latter is unclear but we know that some cases will turn out tube something else. I can see no value in trying to extract a number.

 

Can we even say that we have evidence that it happens? If you wanted to say this in a paper, could you back it up?