SINGAPORE: Nine lots of a brand of HIV screening test kits have been recalled, after it was found that the kits could result in false negative results for some people in the early stages of an HIV infection, announced the Health Sciences Authority (HSA) on Monday (Jun 5).
The affected lots of SD Bioline HIV Ag/Ab Combo were supplied to 26 clinics and as well as the National University Hospital (NUH), and they were issued an urgent notice by the kits’ local importer Unison Collaborator on May 11.
NUH and the clinics were advised to stop using the kits and to retest people who had tested negative using the affected lots.
“According to the manufacturer, when a patient is in the very early window period, the lower sensitivity of the affected lots may reduce detection, with the possibility of a false negative result for this subset of patients,” said HSA in a news release.
In response to media queries, HSA said it does not know how many people were tested with the affected kits as it does not have data on the usage of such test kits.
It did say, however, that a total of 584 kits were supplied to the healthcare facilities. Of these, 547 kits – each containing 25 tests – have potentially been used, it added.
SD Bioline HIV Ag/Ab Combo is a rapid HIV Antigen and Antibody combo test, which allows users to screen for an HIV infection earlier. There is usually a window period of up to three months during the early stages of infection when blood tests may be unable to detect the virus, but rapid test kits are able to shorten that window period.
As a precautionary measure, HSA said all 36 healthcare facilities in Singapore supplied with this brand of test kit – not only the affected lots – have been told to stop using them and to turn to other brands of rapid HIV test kits until further notice.
It added that people with high risk of HIV exposure who have taken a rapid HIV test between February 2016 and May 2017 should to check with their clinic on the need for a re-test.
The list of healthcare facilities supplied with the affected lots can be found here.
HSA also stated that all rapid HIV tests are not meant to confirm an infection and are to be used only as an initial screening test.
Positive rapid test results must be confirmed by sending a blood specimen to a clinical laboratory for Enzyme Immunoassay (EIA) testing and further confirmatory testing by Western Blot if necessary.