Yorkshire children face six-month autism test wait
Children identified as being potentially autistic have to wait an average of almost six months for an initial assessment in Yorkshire.
National guidelines recommend children are seen within three months of referral.
Of 2,026 Yorkshire children currently in need of assessment, 913 have exceeded the target timeline.
A spokesperson for The National Autistic Society (NAS) said long delays could be "devastating" for families.
Research by the BBC found NHS Airedale, Wharfedale and Craven Clinical Commissioning Group (CCG) had the longest average wait at 47 weeks.
Of the 190 children in current need of assessment, 148 have already waited for more than three months.
Vale of York CCG had the second longest average wait at 34 weeks.
Bassetlaw CCG and Sheffield CCG reported the shortest average waits at four and six weeks respectively.
Autism is a developmental disorder that can cause problems with social interaction, language skills and physical behaviour.
Lindsay Hale, from Skipton, has been waiting for her four-year-old daughter, Dotty, to be assessed since April.
She said: "It's heartbreaking because we just see a little girl that wants to play and be happy, but nobody understands her.
"We just want to be supportive parents. There are specialists out there that can give us the support but we're having to wait.
"It's extremely frustrating. I do not understand why we have to wait so long."
According to research, the average wait for children from raising concerns to final diagnosis is more than three-and-a-half-years.
The NAS said that as a result one in 10 people paid for a private diagnosis.
Janine Booth, who helps to run an autism support group in Dewsbury, paid £5,000 to have her son Alex assessed.
"It's opened Alex's world up, it's opened our world up," she said.
"Unfortunately other children are missing out."
Dr Phil Pue, chief clinical officer at NHS Airedale, Wharfedale and Craven CCG, said a review of its autism pathway had identified areas that needed improvement and it was hoped a new service model would be in place later this year.
A spokesperson for NHS England North said it was working with local CCGs to "identify and overcome the reasons behind any delays".