Questions have been raised after some high profile figures - who presented mild or even no symptoms - were able to get tests when others cannot.
The current Public Health England (PHE) criteria for testing divides patients into two categories:
Inpatients, requiring hospital admission:
Patients who have been deemed ill enough to require spending at least one night in hospital meet the criteria for a Covid-19 test if they also have:
Either clinical or radiological evidence of pneumonia or
Acute respiratory distress syndrome
Influenza like illness with respiratory symptoms including a persistent cough, hoarseness, nasal discharge or congestion, shortness of breath, sore throat, wheezing, sneezing
PHE guidelines also note that inpatients could meet the criteria for a test if they develop "new respiratory symptoms or fever without another cause" or if a pre-existing respiratory condition get worse.
Patients well enough to stay out of hospital:
Not everybody who meets the criteria for a coronavirus test has to be hospitalised - evident in some of the high profile confirmed cases reported.
For patients staying at home in self-isolation, a test could be administered if they develop a "new continuous cough" and/or "high temperature".
Guidance says clinicians should be "alert" to "atypical" symptoms in patients who are "immunocompromised" - a high risk group.
Medical staff are also being encouraged to consider "alternative clinical diagnoses and epidemiological risk factors" when deciding whether to test a patient.
Despite the relatively strict criteria for testing, social media users have queried how high profile figures have secured tests for the virus.
The statement added: "The tests were carried out by the NHS in Aberdeenshire where they [Charles and Camilla] met the criteria required for testing."
The NHS Scotland website says people will only generally be tested for Covid-19 if they "have a serious illness that requires admission to hospital".
But a member of the Scottish Parliament expressed surprise Prince Charles was tested for Covid-19 on the NHS.
Joan McAlpine, SNP MSP for the South of Scotland, tweeted that she wishes Charles a speedy recovery, but added:
"Given that his symptoms are said to be mild, like many I wonder how he was tested when many NHS and social care workers cannot get tested."
Scotland's Chief Medical Officer Catherine Calderwood said: "I've discussed with the team in NHS Grampian and from the information I've been given it's clear he was tested for clinical reasons".
In a video on his Twitter page, the Luther star explained he had been in contact with a person who had tested positive for coronavirus.
He said: "It was definitely something that I had to do because I was around a lot of people.
"Quite honestly, my job made me test immediately. I had to test anyway because it meant putting a lot of people at risk if I had been exposed."
The actor said: "We got a test immediately, and we were really lucky to get a test immediately because of the shortage of tests".
The 47-year-old admitted "getting a test is really, really hard" and said - had he not been at work - it would have been harder for him to secure a test kit.