Nicola Sturgeon has played down a row with the UK government over delays to Covid-19 tests in Scotland, saying she has no interest in a “war of words”.
Only 316 new cases of the virus were reported on Sunday – a dramatic drop from 1,167 on Saturday.
The Scottish government said this was due to tests being diverted from the UK government’s Lighthouse lab in Glasgow to other sites across the country.
The UK government spokeswoman insisted this was “categorically untrue”.
However Ms Sturgeon said the governments were “working very hard” to improve turnaround times for tests and did not disagree on the “substance” of the issue.
She said there were “intermittent frustrations” about the testing system, but said people should have confidence that it “does work”.
The number of positive tests registered jumped back to 993 on Monday, with the number of people in hospital also continuing to rise.
After the figures for Sunday bucked the recent trend, a post on the Scottish government website claimed that “demand from outwith Scotland” had caused a delay in test results coming back from the Lighthouse lab in Glasgow, with swabs being redirected elsewhere.
The UK government issued a response insisting there was “no capacity issue at the UK government’s Glasgow Lighthouse lab”, and that “rerouting tests to other laboratories is a routine practice to ensure timely processing”.
At her daily coronavirus briefing, the first minister said it was “not in anybody’s interest to have a war of words”.
She said: “We are working very hard with the UK government to ensure turnaround times, particularly for tests that are already taking longer than we would want, are as quick as possible.
“When I looked at the UK government statement I’m not sure they are denying or challenging the substance of what I am saying – it recognises that a large number of tests have been diverted to labs elsewhere in the UK.
“We hope that redirection will have stopped as of yesterday.”
Ms Sturgeon said tests from drive-through centres – which are usually taken by people who have symptoms and are thus more likely to return positive results – were among those diverted, which she said “might explain” why Sunday’s figures were “probably artificially low”.
Allan Wilson, who is president of the Institute of Biomedical Science, based at Monklands hospital in North Lanarkshire, told BBC Radio’s Good Morning Scotland programme the problem was that no one understood how the Lighthouse laboratories operate.
He said: “The issue we have with the Lighthouse lab is that there is a lack of transparency to what happens in that lab because it is not part of the NHS testing, it is delivered through the UK government and it is difficult to find out what the actual issues are until we actually hit problems like we just hit.
“They work as a network, so they move samples around the country if there are problems. That in itself increases turnaround time and delays results getting back. They did have an issue with staffing, certainly when staff returned to academic institutions, when universities started back, and we know they are actively recruiting.
“What we are calling for is more transparency. If the Lighthouse labs worked more in collaboration with the NHS labs we would be able to work between the two more easily and focus on those samples and results that are needed urgently.”
People across Scotland are currently banned from visiting other people’s homes, and tougher restrictions on licensed premises were introduced earlier this month.
Temporary measures in the central belt have led to the closure of pubs and restaurants in the Greater Glasgow and Clyde, Lanarkshire, Lothian, Forth Valley and Ayrshire and Arran NHS board areas.
Those living in these areas have been warned not to travel to other parts of Scotland or to areas in England where such restrictions are not in force.
These measures are due to expire on 26 October, to be replaced by a new “strategic framework” for suppressing the virus.
Ms Sturgeon is drawing up plans for a “three-tier framework” of alert levels which would trigger different restrictions, either on a local or national basis.
This will be set out at the end of the week, with MSPs set to debate and vote on the plans when Holyrood returns from the half term recess.
Ms Sturgeon said this was an “important step as we look ahead to winter”, which would be a “very challenging period”.