NHS England 'must monitor waits for autism diagnosis'
The amount of time it takes for autism to be diagnosed should be monitored by NHS England, the National Autistic Society (NAS) says.
The charity says delays between being referred to an autism specialist and diagnosis are "unacceptably long" and putting "families into crisis".
A report by Public Health England has shown there is a huge disparity in waiting times across England.
NHS England says it is committed to reducing waiting times.
The NAS says it can take on average over two years for children and adults to get a diagnosis, if the time it can take to get a referral from a GP is considered.
Jane Harris, director of external affairs at the NAS, told the Victoria Derbyshire programme the situation had to change.
"At the moment people are waiting months - if not years - for a first appointment. If they're adults that might mean losing their job, if they're children they might be excluded from school. It can be really difficult.
"You can know that there's something wrong but not what. At least when you know, there's then a coping mechanism to deal with it, people know where to get support."
The Public Health England report, published last month, showed that some people in the South West of England were waiting as long as 95 weeks between a referral to an autism specialist and a diagnosis.
The wait was as long as 90 weeks in South East and 84 weeks in Yorkshire and Humber.
The median wait across England was 13 weeks. The national guidelines from NICE say the wait between referral and diagnosis should not exceed three months.
The NAS says an increase in autism awareness has led to more referrals, meaning there are huge delays in the system.
But it says the real issue stems from a lack of monitoring. The reasons for the delays could differ in each region and without monitoring of waiting times, it is hard to know why there are backlogs, and what is needed to fix the problem.
Ms Harris added: "The NHS needs to look at autism in the way it looks at other treatments - there's a waiting time for conditions from depression to hip operations."
An NHS England spokesman said: "Diagnosis of autism spectrum disorders should of course happen as soon as possible, but is often complex and involves many different professionals and agencies.
"This is an issue we take very seriously and we have committed to working with local areas to identify and overcome the reasons behind long waiting times. We'll continue to work with NAS and others to make sure people with autism can get the help they need, when they need it".
A Department of Health spokeswoman said: "The guidelines on autism make it crystal clear that families should wait no more than three months to start diagnosis. Every bit of the NHS should be adhering to these guidelines and NHS England is working with local areas to make sure these waiting times are cut."
The Victoria Derbyshire programme is broadcast on weekdays between 09:15 and 11:00 on BBC Two and the BBC News channel.