People who also tested positive were told they were negative.
An Ontario COVID-19 test error led 15 people to mistakenly believe they had tested positive.
The Hamilton Regional Laboratory Medicine Program reported on Sunday that a total of 31 individuals had received incorrect test results.
According to HRLMP, the tests were conducted in Hamilton, Burlington and other nearby regions on December 30 and 31.
To make matter worse, 16 people were also initially told they had tested negative when they actually did have COVID-19.
“Of the 31 individuals, 16 who were COVID-19 positive initially received a negative test result and 15 who were COVID-19 negative initially received a positive test result,” an excerpt reads.
Hamilton Public Health has reportedly been in contact with the individuals who received inaccurate results.
Ontario confirmed 3,338 more cases of COVID-19 on Monday morning.
Premier Doug Ford is scheduled to announce more restrictions on Tuesday.