Health Canada recalls Innovacon pregnancy tests over false positive risk

Health Canada is issuing a safety notice and recall for HCG one-step pregnancy tests from Innovacon Inc. over concerns that they may show a false positive result.

"The product may detect low levels of HCG below the stated assay sensitivity, which may result in false-positive test results in samples from non-pregnant individuals," the agency wrote in the notice.

"The package insert is being updated to note that low HCG levels can occur at or after the onset of perimenopause. Customers should consider this when interpreting results," the warning added.

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Rapid response tests are used for the early detection of pregnancy by determining the presence of human chorionic gonadotropin (HCG) in urine.

It is a hormone produced in the placenta, and its levels begin rising after a fertilized egg implants in the uterus.

During early pregnancy, the amount of HCG in blood and urine doubles every two to three days, the Mayo Clinic says.

That means waiting a day or two after a missed period to take the test makes it more likely that it will detect HCG and show a positive result.

Most tests produce a result within a few minutes.

Many home pregnancy tests claim to be 99 per cent accurate, but several factors can impact the results or lead to a false positive.

A false positive might happen if a miscarriage occurs soon after the fertilized egg attaches to the uterine lining, the Mayo Clinic notes.

It also says a false positive is possible if a person takes a pregnancy test soon after taking fertility medicine that contains HCG.

HCG is present in the body only during pregnancy, the clinic added, though problems with the ovaries and menopause may also lead to a false positive test result, it warns.

Irregular menstrual cycles can also impact pregnancy test results, as they can make it hard to decipher when a period should start.

Home pregnancy tests can also vary in sensitivity.

More sensitive tests need less HCG in urine to show a positive result.

On the contrary, false negatives are more likely if a person takes a test too soon.

The most accurate results usually occur the first day after a missed period.

Pregnancy tests have been recalled in Canada before, for issues ranging from unreliable results to faulty packaging.

The recall for the Innovacon tests follows a pattern of recent safety actions by Health Canada.

Novello Desserts reported in October that Health Canada and the CFIA issued new recalls for hand warmers, strollers and raspberries over fire, burn and norovirus hazards.

On the same day, Health Canada also recalled the Valco Baby Trend Duo Double Stroller because 314 units sold in Canada did not meet federal carriage and stroller regulations.

With files from Global News