"I had only two choices," said Mustaq from Afghanistan, one of those assessed told Radio Sweden as he visited a dentist in Eskilstuna to have his wisdom teeth X-rayed.
"Either I volunteered to have a medical age assessment, or I would have had to let the Migration Agency judge my age."
Since March, the Migration Agency has referred 4,200 people who have volunteered to have an age test, to the National Board of Forensic Medicine.
The tests to establish whether a person is an adult or not is done by x-raying their wisdom teeth and by an MRI-scan of their knee joints. These scans are then assessed by two different doctors independently.
"Normally the knees are fully matured after the age of 20 and the teeth are just below 20," explains Ann Lemne, who led the project for the board.
"We've chosen methods that as far as it's possible will not judge children as grown-ups."
So far, 581 cases have been assessed and in 442 of them, the results "suggests that the assessed person is 18 or over".
A further five cases were deemed "possibly" 18 or over. The remaining 124 cases were deemed to "possibly suggest that the assessed is under 18".
The Migration Agency estimates that up to 14,000 people will undergo a test like this to establish whether they are older or younger than 18.
The first tests took two months to process which Lemne admitted was longer than had been anticipated, leaving people like Mustaq still waiting for their result.
"It's not just me. All of us are waiting for a decision from the Migration Agency," he told Radio Sweden. "It's really tough. It's the only thing we think about."