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What is SCRiPS?

SCRiPS is an online calculator that public health experts can use to help develop COVID-19 screening and testing protocols. SCRiPS calculates the risk of a positive covid-19 test based on factors such as age, sex, travel history, symptoms and the local level of COVID-19 (percentage of positive tests).

SCRiPS is based on the peer-reviewed study Derivation and Internal Validation of a Model to Predict the Probability of Severe Acute Respiratory Syndrome Coronavirus-2 Infection in Community People, published in the Journal of General Internal Medicine (2020) by Dr. Carl van Walraven and colleagues (DOI: [10.1007/s11606-020-06307-x]).

Can I use SCRiPS to decide whether I should be tested for COVID-19?

Do not use SCRiPS to decide whether you should be tested for COVID-19. Follow recommendations from your local public health department when deciding whether you should be tested for COVID-19.

Local criteria for testing COVID-19 typically include many factors beyond those in the SCRiPS Score, such as the availability of testing and the local COVID-19 infection rate.

Can health care providers use SCRiPS?

The algorithm is not for clinical use. SCRiPS requires further development and validation before it could be recommended for clinical use.

Further development studies include validation of SCRiPS in other settings (testing centres). As well, the risk of factors such as travel and work have changed since SCRiPS was developed in spring 2020 (see below). Furthermore, symptoms such as loss of smell and stomach symptoms were not included in SCRiPS because these factors were not known to be associated with COVID-19 infection at the time. It would be helpful to re-evaluate risk factors that were used to develop SCRiPS. Finally, there are additional steps to assess whether algorithms such as SCRiPS improve clinical care, such as acceptability by patients and providers.

Why is SCRiPS helpful?

SCRiPS can provide public health experts with insights to help develop screening and testing protocols. SCRiPS shows what factors are (or are not) associated with COVID-19 positive infection. For example, one of the most influential predictors of a positive COVID-19 test is the background rate of COVID-19 in a given community. SCRiPS uses information about the level of COVID-19 infection using the question, "what is the case detection rate in your community in the past 3 days? (percent of people tested with a positive covid-19 result)".

Fever is another factor that was studied. In SCRiPS, fever is associated with a high risk of a positive COVID-19 test in younger people, but not in older people. These insights inform how to best design COVID-19 screening and testing strategies.

How was SCRiPS developed?

SCRiPS was developed using the results of people who were tested for COVID-19 at the Brewer Assessment centre in Ottawa between March 13, 2020 and April 21, 2020. The testing centre was operated by The Ottawa Hospital and the use of patients’ data for this study was approved by the Ottawa Health Science Network Research Ethics Board.

9172 patient tests were used to develop SCRiPS, of which 571 tests were positive for COVID-19 infection. Prior to their COVID-19 test, patients were asked questions by the testing centre staff about why they were being tested for COVID-19, along with additional questions about symptoms. These questions were analysed to calculate which questions were related to a positive COVID-19 test.