Mobile testing units and "walk-through" centres are being brought in to deal with a spike in demand across Scotland.
Nicola Sturgeon confirmed the expanded capacity after Scots were wrongly sent to England during exceptional demand.
It led to claims the Scottish Government were slow to react when it was clear demand would increase with schools going back.
At the regular coronavirus briefing today, Sturgeon insisted she had been prepared and said the surge led to a "technical issue".
Sturgeon said three more mobile units will be brought in across the central belt, including one immediately in Glasgow, which will expand capacity by up to 1500 tests a day.
Testing capacity will be increased in NHS and regional centres.
Greater Glasgow and Clyde health board are opening drive-throughs. And 11 local "walk-through" centres will open, with the first in St Andrews which is braced for an influx of students.
Sturgeon said: "Over the weekend, there was a major spike in demand for testing – not just in Scotland, but we think across the UK.
"That led to some constraints on the booking portal throughout the day yesterday and that, in turn, resulted in a surge of calls to our Covid-19 helpline.
"I know this will have been frustrating for people trying to book a test so I want to thank everyone for bearing with us as we’ve worked to address these issues."
Sturgeon said "contingency plans are already being activated" in order to increase Scotland’s test capacity.
