9,000 potentially incorrect HIV test results

A total of 9,000 patients at testing centers at Lakeshore, St Mary’s and LaSalle hospitals have potentially received a false negative HIV infection result. In early September, the manufacturer, Ortho Clinical Diagnosis, reportedly reported an issue with one of the components of two lots of the test used between January and June 2022.

As soon as it was informed by the manufacturer, the Optilab laboratory of the McGill University Health Center (MUHC) was able to identify 9,000 patients from its screening centers. Optilab-MUHC Montreal then retested 3,000 samples from previous tests performed on pregnant women. All retested samples again tested negative, confirming the original result.

According to the Federal Government Health Product Recall site, the manufacturer has received a customer complaint of false negative results from the use of the VITROS HIV Combo Test reagent set.

After conducting an investigation, Ortho Clinical Diagnosis has concluded that the problem relates only to the detection of the HIV p24 antigen. The latter is detectable in the first weeks following infection. The component of the test for detecting an established infection was therefore not defective.

According to the Ministry of Health and Social Services (MSSS) of Quebec, other laboratories have also used defective tests. The laboratories concerned are: Montreal-MUHC, Mauricie-Centre-du-Québec and Saguenay—Lac-Saint-Jean.

“It was theoretically possible, in rare circumstances, for patients tested in a very early phase of HIV infection to obtain a false negative result,” explains the ministry. According to the information provided by the supplier, this situation was only very rarely reported by all of the users of these kits”.

Asked by Metro As for the number of results that turned out to be false negative, the Ministry of Health and Social Services explained that it had not received this information for the moment. However, he explains that the batches in question are no longer used and that the supplier has ensured that the problem is corrected.

An action plan put in place

At the end of September, Optilab-MUHC Montreal sent letters to 1,700 doctors so that they could inform their patients. A bank of “high priority” appointments on Clic Santé has been set up to facilitate appointments for the patients concerned and nurses have been mobilized to respond to telephone requests from doctors and patients.

“It is extremely unlikely that we will discover false negative results, but at Optilab Montreal-MUHC, we have decided not to take any risks,” explains a spokesperson for the MUHC.

It was only at the beginning of last December that the MUHC sent “personalized” letters to patients.