People using community coronavirus testing centers in England wait longer for their results, the data show.
Only a third of the tests carried out in the community offices returned in the 24 hours of the week until 9 September.
This is down from two-thirds the week before, NHS Test and Trace said.
Access to community testing has had to be rationed as labs are struggling to keep up with demand, but this is the first evidence that tests occurring take longer to process.
There are three types of community test centers: drive-throughs, walk-in centers, and mobile units that are deployed in hotspot areas.
All three have seen increases in delivery times.
- Average turnaround times for regional drive-through centers increased from 20 to 27 hours, with 38% returned in 24 hours
- For local walk-in centers, the average was 35 hours, with only one in five results delivered within 24 hours
- Mobile units fared better with an average of 26 hours, compared to 1
360,000 tests were performed in these three settings during the week, up from about 320,000 in the previous week.
The lead time release comes as an increasing number of people complain that they can’t access tests at all.
Reservation slots at test sites and the availability of kits that are posted in people’s homes have been limited across the UK as labs are unable to keep up with demand.
This meant that testing had to be a priority for high-risk areas, including nursing homes and areas where local outbreaks exist.
Experts warn that the problems will limit the UK’s ability to contain the spread of the virus.
The hospital laboratories, which process tests for patients and NHS staff, are not affected by the problems. Nearly nine out of 10 tests are performed in 24 hours.
The government said the testing capacity will increase. Currently 375,000 tests can be processed per day, although only about 160,000 of these are in the community testing labs.
Two new labs are expected to open soon, which would bring overall capacity to 500,000 by the end of October, with two more expected in early 2021, the government said.
Baroness Dido Harding, head of NHS Test and Trace, said: “We are working tirelessly to increase testing capacity so that anyone who needs a test can get one.
“I can’t stress enough how important it is that only those with symptoms book tests. The service is there for those suffering from a high fever, continuous new cough or loss or change in the sense of taste or smell.
“If you have no symptoms but think, or have been told by NHS Test and Trace that you have been in contact with someone with the virus, stay home but don’t book a test,” he said.
“We need everyone to help ensure that tests are available for people with symptoms who need them.”