A new study believed to be the largest of its kind found that antigen rapid tests were overall 81 per cent accurate when compared with PCR test results, and were more accurate the more symptomatic a person was, adding more support to the idea that these tests could be used more widely.
Between Dec 23, 2020 and Jan 11, 2021, more than 6,000 people came to the Baltimore Convention Center Field Hospital (BCCFH), where researchers gave them PCR tests as well as rapid antigen tests.
The results surprised researchers, with the antigen tests showing an overall sensitivity of 81 per cent. Sensitivity refers to how well a test can correctly identify if a person has the virus or not.
“We found that virus was accurately detected by the rapid antigen test in 87 per cent of patients with COVID-19 symptoms and in 71 per cent of those who were asymptomatic — rates that surprised us because they were so high,†Dr. Zishan Siddiqui, assistant professor of medicine at the Johns Hopkins University School of Medicine and study lead author,
“This is a significant finding because the rapid test offers a number of advantages over the PCR test, including time savings, both in sampling and processing; cost savings; and most importantly, ease of distribution and application — basically anywhere — which can help overcome COVID testing disparities in medically underserved communities.â€
Participants at BCCFH who received tests self-reported on their symptoms, and whether or not they believed they had been exposed to COVID-19. The majority of participants were asymptomatic, with 89 per cent not presenting with any symptoms.
Among those asymptomatic individuals, the reasons for desiring a COVID-19 test ranged from living with a person with confirmed or suspected COVID-19 and having been within six feet of someone with confirmed or suspected COVID-19, among other types of exposure.
For those with symptoms, 89 per cent were tested within a week of developing their first symptoms.
The rapid test was 99.8 per cent accurate at identifying when someone did not have COVID-19, which is called a test’s specificity.
In symptomatic patients, sensitivity was higher than among asymptomatic patients, while the specificity was very high regardless of symptoms.
For asymptomatic patients, the test sensitivity was 80 per cent for those who reported living with a person with COVID-19, and 73 per cent for those who had been within six feet of someone with COVID-19.
“Despite the high negative predictive value, patients with negative results represent a large proportion of total positive cases,†“Hence, a negative result does not preclude infection from a clinical and public health perspective.â€
Quality checks of a random assortment of the antigen tests performed found that only 0.5 per cent of tests were indeterminate.
The study specifically used the BinaxNOW rapid antigen COVID-19 test, a test available in the U.S. but not in Canada, according to Health Canada’s list of authorized testing products.
While PCR tests are still the gold standard in accuracy for testing for COVID-19, they require trained staff, more special equipment and have to be sent off to a laboratory for testing. The benefit of rapid testing is that they are easier to conduct, can be administered outside of clinical settings, and provide results in around 15 minutes — which could be a huge help in letting people know fast if they need to quarantine.
“What we determined was that while the PCR test may be a better test from a clinical perspective — as it’s basically 100 per cent accurate at detecting SARS-CoV-2 — the rapid antigen test appears to be better from a public health standpoint because of its ease of use, and the fact that it proved to have sufficient accuracy, specificity and reliability for detecting the coronavirus in a high-volume setting,†Dr. James Ficke, professor of orthopaedic surgery at the Johns Hopkins University School of Medicine and co-director of the BCCFH, said in a press release.
“The field hospital was the perfect place to determine this because we could see how well both tests worked for a large number of people in a short amount of time.â€
The study noted that 81 per cent sensitivity is higher than the 80 per cent threshold that the U.S. Food and Drug Administration has set for emergency use authorization, and that while the sensitivity is lower in asymptomatic patients, rapid testing could be considered for screening purposes.
The team is currently running tests comparing antigen testing with PCR testing in children, and have collected data on around 1,000 children so far. They hope to release that data in early 2022.
The Israeli military targeted a top Hezbollah figure in a strike on Beirut's southern suburbs on Friday, two security sources in Lebanon said, sharply escalating the year-long conflict between Israel and the Iran-backed group.
Smoke is rising over Lebanon’s capital of Beirut Friday after Israel’s military struck southern suburbs – a dramatic escalation in a year-long period of conflict between Israel and Hezbollah.
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The Montreal couple from Mexico and their three children facing deportation have received a temporary residence permit.
A 20-year-old man and his co-conspirator have been charged with conspiracy to steal and launder over US$230 million in cryptocurrency, and federal authorities said the arrests are connected to an FBI raid of a mansion in Miami.
The federal firearm buyback program has cost taxpayers nearly $67.2 million since it was announced in 2020, but it still hasn't collected a single gun.
Since she was a young girl growing up in Vancouver, Ginny Lam says her mom Yat Hei Law made it very clear she favoured her son William, because he was her male heir.
The Montreal couple from Mexico and their three children facing deportation have received a temporary residence permit.
Emergency crews in northern Ontario found the bodies of four people inside a home where a fire broke out Thursday night.
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Five bison are dead at Elk Island National Park east of Edmonton following an early Thursday morning collision.
Lawmakers are scrambling to ensure that the U.S. Secret Service has enough money and resources to keep the nation's presidential candidates safe amid repeated threats of violence. It's unclear, though, how much they can do with only weeks before the election, or if additional dollars would make an immediate difference.
The mayor of a French town making headlines for the trial of dozens of men accused of rapes that occurred there over almost a decade has apologized for comments that appeared to downplay the case.
A federal law enforcement agency confirmed it's opened an investigation into Robert F. Kennedy Jr. after he allegedly cut off the head of a dead whale and took it home two decades ago.
Smoke is rising over Lebanon’s capital of Beirut Friday after Israel’s military struck southern suburbs – a dramatic escalation in a year-long period of conflict between Israel and Hezbollah.
Lawyers representing dozens of women who say they were raped and sexually abused by Mohamed Al Fayed, the former boss of the famous London department store Harrods, said the case was akin to the crimes of sex offenders Jimmy Savile, Jeffrey Epstein and Harvey Weinstein.
A 20-year-old man and his co-conspirator have been charged with conspiracy to steal and launder over US$230 million in cryptocurrency, and federal authorities said the arrests are connected to an FBI raid of a mansion in Miami.
Prime Minister Justin Trudeau tapped Treasury Board President Anita Anand to take on additional duties as Canada's minister of transport on Thursday.
Conservative Leader Pierre Poilievre and NDP Leader Jagmeet Singh got into a heated exchange in the House of Commons on Thursday, just minutes after Singh announced his party would not be supporting the Conservatives' first non-confidence motion against Prime Minister Justin Trudeau's government.
The head of Via Rail repeatedly told MPs a train delay over the Labour Day long weekend was an isolated incident, despite a similar event two years ago.
The Nunavut government says it will provide immunization against respiratory syncytial virus to all infants in the territory this fall, a policy change that one pediatric infectious diseases specialist has been advocating for decades.
Ontario’s Minister of Sport, Neil Lumsden, will donate his brain to research.
Software company Mustimuhw Information, which develops medical records systems built on a foundation of Indigenous traditions and values, is allowing health providers to capture data informed by cultural practices.
Lebanese authorities on Thursday banned walkie-talkies and pagers from being taken on flights from Beirut airport, the National News Agency reported, after thousands of such devices exploded during a deadly attack on Hezbollah this week.
If something looks too good to be true, it might be. That's the message from Saskatchewan horticulturists after customers have come into their stores hoping to buy purple apple trees this month.
NASA scientists have successfully replicated spider-like shapes found on the surface of Mars in a laboratory setting for the first time.
Lawyers representing the producers of 'Russians at War' say they may pursue legal action against Ontario's public broadcaster for pulling support for the controversial documentary amid outcry from the Ukrainian community and some Canadian politicians.
Viewers of Jeopardy got a chance to test their knowledge of trivia about B.C.'s biggest city Wednesday night.
British actress Florence Pugh has revealed that shaving her head for her latest movie role was a 'really bizarre' experience that sent her body 'into a bit of trauma.'
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Toronto Blue Jays shortstop Bo Bichette returned to the 10-day injured list Thursday due to a right middle finger fracture.
An Ontario man says it is 'unfair' to pay a $1,500 insurance surcharge because his four-year-old SUV is at a higher risk of being stolen.
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Getting a bed at one of British Columbia's drug detoxification facilities is like winning the lottery, the vice-president on the Nuu-chah-nulth Tribal Council says.
B.C.'s police watchdog is investigating the death of a woman who was shot by the RCMP after allegedly barricading herself in a room with a toddler early Thursday morning.
The Israeli military targeted a top Hezbollah figure in a strike on Beirut's southern suburbs on Friday, two security sources in Lebanon said, sharply escalating the year-long conflict between Israel and the Iran-backed group.
For the last seven-and-half months, Toronto resident Heather McArthur has been living out what she describes as her 'worst nightmare.' On Feb. 7, her then three-year-old son Jacob along with his father Loc Phu 'Jay' Le departed for what was supposed to be a week-long visit to Vietnam to celebrate the Lunar New Year with family, McArthur says.
An Ontario man says it is 'unfair' to pay a $1,500 insurance surcharge because his four-year-old SUV is at a higher risk of being stolen.
Ontario police say they have arrested four members of the Hells Angels Motorcycle Club (MC) and seized a number of firearms after an alleged assault and robbery in Hamilton in July.
Defence counsel for accused murderer John-Christopher Arrizza argues he was in an “altered state of mind†due to days of drug and alcohol use, sleep deprivation and not eating, when he fatally stabbed a man at a Banff nightclub in 2022.
Injury prevention experts are urging Calgarians to ride carefully as e-scooter crashes land hundreds of people in the hospital.
Friday will be cool and wet with intermittent showers likely through most of the day.
CTV News has learned “significant news†is coming Friday regarding ongoing discussions to build a new downtown arena for the Ottawa Senators.
A man has been taken to hospital in life-threatening condition following a stabbing incident that happened on Baseline Road in the early hours of Friday morning, according to the Ottawa Paramedic Service.
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The Montreal couple from Mexico and their three children facing deportation have received a temporary residence permit.
The province's public security minister said he was "shocked" Thursday amid reports that a body believed to be that of a 14-year-old boy was found this week near a Hells Angels hideout near Quebec City.
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The big weather story today won't really be rain, it'll be the cooler and breezier conditions.
Five bison are dead at Elk Island National Park east of Edmonton following an early Thursday morning collision.
Gas prices increased in all three Maritime provinces for the first time in more than a month.
A Nova Scotia woman has applied for a medically assisted death, saying after years of battling to receive out-of-country surgery for an illness that causes "indescribable" pain, she struggles to maintain the will to live.
A section of Herring Cove Road in the Spryfield area of Halifax is closed to traffic in both directions following a single-vehicle collision Friday morning.
The Winnipeg Police Service (WPS) has made an arrest following a fire that claimed the lives of two people.
Shamattawa RCMP are searching for a missing six-year-old boy who hasn’t been seen since Wednesday morning.
A Winnipeg pet rescue is putting out a warning to dog owners across the city about a possible parvovirus in the province.
Driving into the tunnels of Nutrien's Rocanville mine, the largest potash mine in the world by production volume, feels like driving down a lonely highway in the middle of the night.
Regina Fire crews were sent to a duplex fire on Dewdney Avenue early Friday morning.
The second-degree murder trial of Thomas Hamp is being adjourned until December so an expert witness central to the trial can testify.
Amber and Adam Brueckner have a pool-shaped hole in their backyard – and their wallets.
The missing family that was last seen in Kitchener, Ont. on Sept. 1 has been found safe, according to police.
Police are trying to identify a man who approached a woman and child in Wellesley.
The second-degree murder trial of Thomas Hamp is being adjourned until December so an expert witness central to the trial can testify.
A gym teacher at a private Christian school in Saskatoon has been charged. Terra MacEwan, 44, is charged with assault with a weapon. A Saskatoon mother who spoke with CTV News says her autistic son was MacEwan's victim.
Driving into the tunnels of Nutrien's Rocanville mine, the largest potash mine in the world by production volume, feels like driving down a lonely highway in the middle of the night.
Emergency crews in northern Ontario found the bodies of four people inside a home where a fire broke out Thursday night.
As northern Ontario gets ready to welcome autumn this weekend, it’s still feeling a lot like summer as provincial forest fire crews continue to battle blazes.
An Ontario man says it is 'unfair' to pay a $1,500 insurance surcharge because his four-year-old SUV is at a higher risk of being stolen.
Police say just before 7:00 p.m. four teens entered a business in the 1000 block of Adelaide Street North.
Police were focusing their attention on the northeast corner of Richmond and Horton, with members of the emergency response unit taking up positions at the scene.
An Elgin County community is expected to double in size as plans for multiple residential developments loom. The Township of Southwold expects shovels in the ground as early as 2025.
Two men from Barrie have been charged after a deadly shooting at a park in Keswick on Wednesday.
A growing group of brides and wedding photographers from across the province say they have been taken for tens of thousands of dollars by a Barrie, Ont. wedding photographer.
Ontario Provincial Police executed a search warrant in Walkerton.
On Thursday, just after 9:30 a.m., a man was found and taken to police headquarters, where he was released with conditions and a future court date.
Standing up, speaking out, and showing solidarity — survivors and supporters gathered in the core to take back the night in Windsor. The city is just one of a growing list of communities that have declared intimate partner violence (IPV) an epidemic.
The Windsor Police Service (WPS) has seized over $56,000 in drugs and have arrested one suspect.
In a rare move, the Greater Victoria School District Board of Education has been slapped with a ministerial order from the province requiring it to update a student safety plan – drawing concern around political posturing leading up to an election.
The Union of B.C. Municipalities is asking the provincial government to make transit free for teenagers.
To appreciate why Mimi Vandermolen is so pleased to notice one particular vehicle she’s walking past, you need to know that seeing this many cars in one place would have been unimaginable when she was growing-up in the post-war Netherlands.
A pair of runaway pigs are in the custody of an animal sanctuary in the Okanagan after evading police and volunteers for hours earlier this week.
The Red Bridge, a historic landmark in Kamloops, B.C., was completely destroyed by fire early Thursday morning.
Animal protection officers in British Columbia have rescued three pit bulls – including one that gave birth to 10 puppies – from a rat-infested home in Kelowna.
A Vulcan, Alta., man has been charged with a Lethbridge woman's murder after her body was found in the Oyen area.
A Lethbridge couple got a good reminder as to why you should keep your vehicle doors locked at all times.
Lethbridge residents who live near the police range can expect to hear plenty of shots fired Wednesday and Thursday.
A new community health profile in the Algoma District shows the area is significantly below provincial averages in a number of health metrics.
North Bay Police Service says one person has died following an industrial accident at the Ontario Northland Transportation Commission Rail Yard on Tuesday.
Three northern Ontario residents are charged with drug trafficking after the vehicle they were in got stuck along a bush road off Highway 17 on Monday.
Newfoundland and Labrador's chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
A 16-year-old biennial event aimed at fostering business in the country's eastern Arctic and northern regions has been cancelled indefinitely as a dispute unfolds between Inuit in Canada and a Labrador group claiming to share their heritage.
Jim Lester’s farm hopped on the cow-cuddling trend in early August, and his time slots have been pretty well sold out ever since.
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