Been told no diagnosis without an informant

(Assumption: you live somewhere with healthcare provided by the UK NHS.  If you are outside the UK, maybe the notes might at least give you some parallel lines to explore in your own territory).

Four observations:

1) "or use documentary evidence" - I wondered if your NHS medical records might include some references applicable to supporting your Autism diagnosis?  I have heard of people accessing their medical records in this manner.  My understanding is you should be able to access your GP records stretching back 10 years.  In an era of tending to have appointments seeing different GPs at different appointments - your medical records might help tie things together a bit more than the latest GP you happen to see.  Here is the NHS England introduction to the subject (I mention it as it can also include your NHS records with your dentist and optician - they deal with you and accommodate your presentation too):

www.england.nhs.uk/.../

2) When it comes to the whole "informant" business, I understand that the key phrase to have in mind here is:

"where possible".

as per guidelines from NICE (National Institute for Health and Care Excellence).

("We produce useful and usable guidance for the NHS and wider health and care system.  Our recommendations help practitioners and commissioners get the best care to people, fast, while ensuring value for the taxpayer").

Autism diagnosis in adults has its own NICE guideline.

National Clinical Guideline Number 142

(Often referred to as: CG142)

Autism spectrum disorder in adults: diagnosis and management
Clinical guideline
Reference number:CG142
Published: 27 June 2012
Last updated: 14 June 2021

www.nice.org.uk/.../evidence

The full guideline document is titled:

"Recognition, referral, diagnosis
and management of adults on
the autism spectrum"

In several places, including within; Summary of recommendations, the following phrase occurs:

""where possible involve a family member, partner, carer or other informant or use documentary evidence (such as school reports) of current and past behaviour and early development."

https://www.nice.org.uk/guidance/cg142/evidence/full-guideline-pdf-186587677

3) "carer or other informant" - if there is not someone who has lived with you long-term, like a life partner, is there maybe someone else - who has been involved in supporting your care in some way over a number of years - who has engaged with you on your good days and your not so good days?

4) as others have said - discuss the assessment provider's apparent pedantic "informant barrier" with your GP.

Personal Footnote:

Not all older adults have a suitable "informant" available - indeed, my personal opinion is that some of the apparently entrenched outlooks expressed by some adult Autism assessment providers feels very close to (effectively) age discrimination. 

It is not our fault we slipped through the assessment safety net until we were older adults. 

I also kick against the "informant" approach also risking denying adults their right to autonomy and confidentiality - by trying to force an adult to disclose their potential Autism status to other relatives (in the quest for identifying an "informant").

(Assumption: you live somewhere with healthcare provided by the UK NHS.  If you are outside the UK, maybe the notes might at least give you some parallel lines to explore in your own territory).

Four observations:

1) "or use documentary evidence" - I wondered if your NHS medical records might include some references applicable to supporting your Autism diagnosis?  I have heard of people accessing their medical records in this manner.  My understanding is you should be able to access your GP records stretching back 10 years.  In an era of tending to have appointments seeing different GPs at different appointments - your medical records might help tie things together a bit more than the latest GP you happen to see.  Here is the NHS England introduction to the subject (I mention it as it can also include your NHS records with your dentist and optician - they deal with you and accommodate your presentation too):

www.england.nhs.uk/.../

2) When it comes to the whole "informant" business, I understand that the key phrase to have in mind here is:

"where possible".

as per guidelines from NICE (National Institute for Health and Care Excellence).

("We produce useful and usable guidance for the NHS and wider health and care system.  Our recommendations help practitioners and commissioners get the best care to people, fast, while ensuring value for the taxpayer").

Autism diagnosis in adults has its own NICE guideline.

National Clinical Guideline Number 142

(Often referred to as: CG142)

Autism spectrum disorder in adults: diagnosis and management
Clinical guideline
Reference number:CG142
Published: 27 June 2012
Last updated: 14 June 2021

www.nice.org.uk/.../evidence

The full guideline document is titled:

"Recognition, referral, diagnosis
and management of adults on
the autism spectrum"

In several places, including within; Summary of recommendations, the following phrase occurs:

""where possible involve a family member, partner, carer or other informant or use documentary evidence (such as school reports) of current and past behaviour and early development."

https://www.nice.org.uk/guidance/cg142/evidence/full-guideline-pdf-186587677

3) "carer or other informant" - if there is not someone who has lived with you long-term, like a life partner, is there maybe someone else - who has been involved in supporting your care in some way over a number of years - who has engaged with you on your good days and your not so good days?

4) as others have said - discuss the assessment provider's apparent pedantic "informant barrier" with your GP.

Personal Footnote:

Not all older adults have a suitable "informant" available - indeed, my personal opinion is that some of the apparently entrenched outlooks expressed by some adult Autism assessment providers feels very close to (effectively) age discrimination. 

It is not our fault we slipped through the assessment safety net until we were older adults. 

I also kick against the "informant" approach also risking denying adults their right to autonomy and confidentiality - by trying to force an adult to disclose their potential Autism status to other relatives (in the quest for identifying an "informant").

Yeah I’ve only very occasionally seen any GP and although I live and work in the U.K. now I don’t have old medical records.  I don’t even think any childhood records even exist: I even just had to get my MMR redone because my childhood doctor didn’t keep records. I’ve also moved country and city a lot (it’s work related). Anyone I’d ask would be on max of 5 years knowing me through work or casual friendship. Or as you noted, I have a few relatives who are a bit older and very anti-diagnosis who, unless the assessor wants to hear the words “a load of nonsense” said repeatedly, won’t be any use. I’m not doing a GP referral because I’ve barely had access to any GP since 2019. I have about 10 photos of me as a child and no other documents as others have suggested, eg school records.