Scotland has recorded 316 new cases of coronavirus but the figures are low due to testing capacity problems creating a backlog.
The delay is due to a capacity issues within the UK Government-run Glasgow Lighthouse facility, the Scottish Government said.
It means around 64,000 tests from across the UK taken between Friday and Sunday will be rerouted to other testing locations – including samples from Scottish regional testing sites such as those at Glasgow and Edinburgh airports.
The Scottish Government said it is “urgently” seeking an explanation from UK officials for what has caused the processing delay, but claimed it is “mainly” a result of demand for tests outwith Scotland.
It expects statistics on positive cases to be high on Monday and Tuesday due to the processing issues.
But the UK Government insisted there are no capacity issues at its Glasgow laboratory.
The 316 new infections reported on Sunday represent 11.2% of newly-tested individuals, but Scottish officials stressed these figures do “not reflect the total number of new cases or new tests”.
No new deaths were reported in Scotland in the last 24 hours, but the government pointed out register offices are now generally closed at weekends.
On Saturday, the country recorded 15 more deaths of Scots with the virus and 1167 new infections nationwide.
There are 703 people in hospital with coronavirus in the country, a rise of 28 in the last day – and a figure which has more than doubled in ten days.
Of those 703 patients, 62 are being treated in intensive care which is unchanged on Saturday’s numbers.
In an explanatory note on testing, the Scottish Government said: “We were notified late last week of a testing capacity issue with the UK Government Lighthouse facility in Glasgow.
“This has meant around 64,000 tests from across the UK, including Scotland, will be rerouted this weekend (Fri-Sun) to other testing sites in the UK and Northern Ireland, including tests from our physical testing sites, for example regional tests sites.
“It is important to note that the majority of these tests are still well within the 24 and 48-hour timeframe for results albeit we do expect to see an increase in the level of positives on Monday and Tuesday when the results are reported.
“The Scottish Government is urgently trying to establish with the UK Government what exactly is causing the delay in testing but this is mainly due to demand from outwith Scotland.
“We continue to reroute routine testing of care home staff through NHS Scotland testing facilities to ensure prompt turnaround times.”
However, a UK Government spokeswoman denied there was any testing capacity issues, saying: “This claim is categorically untrue.
“There is no capacity issue at the UK Government’s Glasgow Lighthouse Lab.
“The Glasgow Lighthouse Lab is highly efficient, with the capacity to analyse tens of thousands of samples a day.
“Rerouting tests to other laboratories is a routine practice to ensure timely processing.”