Opposition parties have expressed concern that official figures show that the processing speed of Welsh coronavirus tests has decreased every week since mid-May.
Just over half of the Covid-19 tests were processed in 24 hours, compared to 68% in late April.
Welsh government advisers say “most effective” contact tracing systems “require test results within 24 hours”.
A government spokesperson said he “is working to fix this problem and expects to see an improvement.”
On June 7, the Prime Minister said that the government had “the ambition” to process as many tests as possible within 24 hours.
But the numbers continued to drop.
In the week before June 21, 50.7% of all tests were completed in one day, 84.4% in two days and 94.1% in three days – the worst set of results since the start of the recordings on April 20.
Most tests – 74,861 in total – were done in coronavirus test units, where only 43.6% of tests are processed within 24 hours and 21% of tests are not processed within 48 hours .
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Speaking to the BBC Politics Wales program, conservative health spokeswoman Angela Burns MS said, “This virus spreads so quickly that in 24 hours, one person could have met an awful lot of people.
“What really worries me is that if we can’t get it now when we all know we are actually well above the coronavirus curve … how the hell are we going to do it right when we’re against, when we’re in the middle of winter? ”
Rhun ap Iorwerth MS, health spokesperson for Plaid Cymru and Senedd member for Ynys Mon, said that the outbreak at the 2 Sisters meat processing plant in his riding was “a very good reason why we need the tests to come back quickly. ”
“We need these test results quickly so that the tracing teams can start their work so that we can find the contacts of those tested positive,” he said.
“Unless you can control the virus and quickly control the epidemics, you tie your hands behind your back and make it difficult to control and hopefully eliminate the epidemics. ”
The Welsh government’s “test, trace, protect” contact screening system means that close contact with people who test positive for coronavirus is asked to self-isolate for 14 days.
Between the start of the new system on June 1 and June 21, 81% of all identified contacts were successfully contacted – a decrease of 88.6% between June 1 and June 14.
Scientific advice from the government’s Technical Advisory Cell (TAC) has indicated that 75-90% of contacts must be traced for the system to be effective.
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The latest contact lists were based on the referral of 1,905 positive cases to local and regional contact tracing teams.
But when asked how many people who tested positive officials could not get in touch with them to find their contacts, a spokesman for the Welsh government said, “We are not currently publishing these data.”
Since the text messaging system for the Covid-19 test results was introduced on April 21, Public Health Wales has reported that tens of thousands of text messages have been sent while “incorrect messages account for approximately 0.02 % “.
Test result sent to the wrong person
A former Labor MP from Kensington was one of the people who mistakenly texted the Covid-19 results.
Emma Dent Coad said, “It wasn’t addressed to me, there was someone else’s name, someone else’s date of birth and it told me that my test result, that I hadn’t had, was negative.
“My first concern was that this poor person did not get the result of his test.
“They told me it was a human error to enter the phone number.
“It worries me even more … they have to have some sort of security mechanism,” she added.
Swansea Bay University Board of Health has stated that the error is treated as a “serious incident” and that they “will consider all possible actions to minimize the risk of something similar happening in the future” .
Prime Minister Mark Drakeford said on Monday about the data breaches, “The more we can automate the system, the more it will be possible to verify that cell phone numbers are not wrongly transcribed when they are transmitted via the This is why we are moving very quickly to the complete electronic system here in Wales.
“There are examples; these are exceptions rather than the rule, but you can see how easily this is done, ”he added.
BBC Politics Wales is on BBC1 Wales at 10:15 BST then on iPlayer after the broadcast.