The first minister was responding to reports that a woman has been given a cardiology appointment at Glasgow Royal Infirmary in July 2024.
Figures released two weeks ago showed that more than 10,000 people in Scotland have been waiting more than two years for NHS treatment.
Ms Surgeon said Covid had significantly impacted on waiting times.
But opposition leaders said the problem was getting worse, with Scottish Conservative leader Douglas Ross saying only 648 patients had waited more than two years for treatment this time last year, but the figure was now more than 10,000.
He highlighted a report in the Scottish Sun that a woman with a heart condition was issued with a telephone appointment with a hospital consultant for July 2024.
Mr Ross also raised the case of Kelso pensioner Alan Turner, who was referred for a knee replacement last autumn. He said Mr Turner was told he would have to wait up to three years to be seen, and was instead offered private treatment in England that was paid for by the NHS in Scotland.
Mr Turner “reluctantly” agreed to travel south for treatment, but then had to wait months for essential aftercare and physiotherapy when he returned to Scotland, Mr Ross said, which had left the 70-year-old “back at square one – he can’t even bend his knee”.
Mr Ross added: “Right now 10,613 Scots have waited more than two years for treatment in Scotland’s NHS – that’s a 16-fold increase on last year. It’s completely unacceptable.
“This isn’t the NHS recovery the SNP promised. Things are getting far worse, not better. Now we’re hearing of heart patients being given appointments two years away.
“These longer and longer waiting times are a problem across every level of Scotland’s NHS. Twice as many Scots are waiting over three months for key diagnostics tests compared to last year.”
Ms Sturgeon said the case highlighted in the Scottish Sun was “not acceptable” and that a review was being undertaken into the patient’s case.
She acknowledged waiting times had gone up, adding: “It is the case that waiting times generally and those waiting an unacceptably long time for treatment has increased over the past year.
“I’m afraid that is the impact of a global pandemic.
“We have, over the past year, seen further waves of Covid that have had a big impact on the number of treatments that can be done in our National Health Service as infection control measures have had to be tightened up and, of course, as a number of staff have themselves had Covid and been off sick.”
The first minister said there was “not a health service literally on the planet” which had not been impacted by the pandemic, and that the government were investing heavily in NHS recovery with record numbers of staff working in the health service.
She went on to say there have been “tentative signs” of improvement in the health service and that “through the efforts of staff” Scotland’s NHS was performing better than those in the rest of the UK on waiting times.
Recent figures for NHS England have shown slightly higher rate of patients on waiting lists than in Scotland, while Wales and Northern Ireland have much longer waiting lists than Scotland and England.
‘Begging for medication’
Scottish Labour leader Anas Sarwar also raised NHS waiting times with the first minister, saying that that there were now 10,000 young people waiting for mental health treatment.
He said he had been contacted by a woman whose son had been diagnosed with autism 10 months ago, but was told he would have to wait to see a psychiatrist before medication could be prescribed.
Mr Sarwar said: “He is still waiting. In that time his condition has become worse, and he is begging for the medication – in his words – to “sort out my head.”
“He is eight years old.”
Ms Sturgeon acknowledged that the Child and Adolescent Mental Health Services (CAMHS) faced “tough challenges” with more and more young people coming forward for treatment.
She insisted there were “signs of improvement” which showed “the highest ever recorded number” start treatment in CAMHS services in the most recent quarter, a 20% increase on the same quarter last year and added that an extra £80m had been invested in the service since 2019/20.
The latest Public Health Scotland (PHS) data showed that 9,672 patients were referred to CAMHS between January and March – 22% more than the same period last year.
About three quarters – 73.2% – were seen within 18 weeks, with the government target being for 90% of patients beginning treatment within that timescale.