AQW 9933/17-22

Ms Claire Sugden
Independent
East Londonderry

Tabled Date: 09/11/2020
Answered On Date: 11/12/2020
Priority Written: No

Question:
To ask the Minister of Health (i) what percentage of COVID-19 testing to date has shown a false positive result in tests carried out (a) at COVID-19 testing centre; and (b) at home; and (ii) for his assessment of the method for collecting swabs from those with COVID-19.

Answer:

Given the different testing platforms and kits that are in use for SARS-CoV2 testing, it is not possible to ascertain an accurate overall false positive rate.

To prevent the reporting of false positives, the laboratory will assess all positives using criteria that may indicate a false positive may be occurring. This criteria includes:

If only 1 gene target out of 2 or 3 gene targets are positive

Weak Ct values (viral load) close to the limit of detection

When these indicators occur repeat testing or testing the sample on a different platform with a different specificity profile is undertaken. This confirmatory testing clarifies the result in most cases.

The Public Health Authority advises that self-swabbing is a recognised method of collecting samples for testing.