Marija Magajne: Between 80 and 90 percent of positive rapid tests show correct result

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State secretary at the Ministry of Health Marija Magajne (Photo: Nebojša Tejić, STA)

By: gov.si

A press conference on the current situation regarding the COVID-19 virus was held by state secretary in charge of vaccinations Jelko Kacin and state secretary at the Ministry of Health Marija Magajne.

365 rapid antigen tests were conducted, of which 23 were positive, or 6.3%. 1,404 PCR tests were also performed, of which 270 (19.2%) were positive. A total of 1,769 tests were conducted, with 293 positive results. According to the data published by the National Institute of Public Health yesterday, the 7-day average number of infections at the national level currently stands at 1,366. 1,237 Covid patients were hospitalised, which is 17 more than on Saturday, and 184 are in intensive care, which is 4 less than on Saturday. A total of 26 patients died, 22 in hospitals and 4 in nursing homes.

Mass testing has been recognised at EU level as one of the measures for preventing the spread of the virus. The advantage of the rapid tests is their availability and simplicity, said Magajne. Their disadvantage is that they are less reliable than PCR tests, and a negative result could give the test recipients a false feeling of security.

The invitation to tender for the public procurement procedure for rapid antigen tests included requirements for submission of documents containing the applicable EU laws that rapid antigen tests have to comply with. No clinical trials of the tests were conducted, since the required documents had to completely demonstrate the efficacy of the test. Magajne compared it with buying aspirin, where the buyer doesn’t check whether the tablet actually contains the correct active ingredient, since this is guaranteed through the relevant permits and certificates.

She explained that there are three types of protocols applying to medical equipment:

– test validation (kit, reagent set): carried out by the manufacturer, which uses it to determine the test’s analytical performance capacities (sensitivity, specificity, positive and negative predictive value, detection threshold, linearity)

– test verification by independent institutions, when deemed necessary, through which the manufacturer’s performance claims are confirmed

– provider confirmation: a test provider confirms that it is capable of conducting the testing according to the manufacturer’s instructions and that it can obtain the expected results If the test provider is unable to confirm this, it may not initiate routine testing. The scope of the verification prior to routine testing is determined by the laboratory itself.

On the basis of anonymised data from the Central Register of Patient Data (CRPD) kept by the National Institute of Public Health, the Ministry of Health conducted an analysis of the results of the rapid antigen tests being used in practice by health service providers in Slovenia. The analysis included all persons who had both a rapid antigen test (RAT) and a PCR test on the same day in the period from 15 November 2020 to 5 January 2021, and whose test result data was sent to the CRPD. Data was available for 1,153 persons. They found that according to this data, the RAT used for mass testing can have up to 81.18% sensitivity and 93.06% specificity in clinical settings (on a sample of 157 persons).

This means that between 80 and 90 percent of positive rapid tests indicate the correct result, which means that they are good at identifying positive cases, and that there are also fewer false negatives than for other types of tests.

The National Laboratory of Health, Environment and Food also carried out the verification of rapid antigen tests supplied by Majbert Pharm. The results of the verification received by the Ministry of Health indicated that:

  • The test meets the manufacturer’s specifications regarding the sensitivity of the test in the group of symptomatic individuals with Ct values of up to 30, and with regard to specificity in the group of asymptomatic individuals;
  • The test satisfies the criteria of the national guidelines for the use of RAT in cases of the results of independent verification of sensitivity in the group of individuals with Ct values up to 33, and with regard to specificity both in the entire group of test subjects, and in the groups of symptomatic and asymptomatic individuals;
  • The test meets WHO criteria for sensitivity without taking account of a 95% confidence interval in the group of all test subjects and the group of symptomatic test subjects, and taking account of a 95% confidence interval only in the group of symptomatic test subjects. With regard to specificity, the test satisfies the criteria both in the entre group of test subjects, and in the groups of symptomatic and asymptomatic individuals.
  • A high level of specificity of RAT was confirmed in the group of asymptomatic individuals, which, assuming that the tests are administered correctly, means that there are very few false positives. The target value of 50 PCR positive subjects was not achieved in this group, and therefore the National Laboratory of Health, Environment and Food will continue conducting the sampling.

Slovenia is participating in an EU-wide joint public procurement procedure for rapid tests. The European Commission will conclude the procedure in the next few weeks, provisionally by the end of January. Slovenia has been guaranteed an adequate number of free high-quality tests. A new public procurement procedure is being drafted for purchasing RAT at the national level.

For the last 10 months, government spokesman Jelko Kacin has been carrying out two separate functions: he has been the government spokesman, and by force of circumstances also the lightning rod for and shock absorber of attacks on the government, which a large part of the public was waiting to shoot down 10 months ago, and towards which certain parties are continuing to sharpen their attitudes.

The amount of work done over that time period is indicated by the fact that in those 10 months, 215 press conferences have been held, at which over 400 people have spoken.

Throughout that entire time, neither Kacin nor any of his key colleagues have contracted COVID-19, since the team has consistently been doing everything it can to be a model for respecting the anti-Covid measures. Kacin has been tested numerous times, with none of the tests returning a positive result.

Kacin also thanked all of the members of the media for their cooperation and reporting, and admitted that the largest responses and highest numbers of comments were to questions asked by journalists.

 

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