When it comes to her kids, Mahone Bay’s Lisa Ali-Learning isn’t taking any chances.
So when her sons, Darian and Lucas, started to complain about joint pains two years ago, she immediately took them to get tested for Lyme disease.
They tested negative.
Months passed and with their health declining, the boys remained undiagnosed as neither developed the tell-tale bull’s-eye rash or other typical symptoms.
The boys finally tested positive for Lyme disease after eight months, leading Ali-Learning to question why it took so much longer to confirm their illness.
She said she was shocked to learn that the universally approved two-tier test is only accurate about 50 per cent of the time in the early stages of the disease.
“It’s a serious, serious disease and you want to know the right answer,” she said.
That’s why Ali-Learning, like a growing number of Nova Scotians, has sought out testing elsewhere; she claims she’s switched to a more accurate test out of a lab in Germany.
“There’s no point in doing the test here, in my opinion, because it’s not accurate enough to get a good read,” said Ali-Learning, who heads AtlanTick Repellent Products Inc., a Mahone Bay business that recently got a federal grant of $100,000 to help boost the production of its natural tick repellent products.
HOW ACCURATE IS THE TWO-TIER TEST?
Dr. Todd Hatchette, the province’s chief microbiologist and a professor of medicine at Dalhousie University, said the accuracy of the two-tier test depends on the stage of the infection.
“In late Lyme disease, it actually works well,” he explained, adding the test is highly accurate in detecting late infections.
But Hatchette said — like Ali-Learning discovered with her children — the test can miss some 50 per cent of early cases.
The variance in early testing results is not unique to Lyme disease; many infections, like measles or HIV, take time to produce enough antibodies to register a positive test.
Hatchette explained that Nova Scotia’s use of the two-tier method, as outlined by health authorities, consists of a first screening ELISA test, which is sent to the QEII in Halifax.
If this test is positive, the sample is then sent to the National Microbiology Laboratory for an immunoblots test before a diagnosis can be given.
However, tell-tale symptoms can supercede testing.
“If you present with early Lyme disease, the recommendation is not to test but to treat because we know that the testing is not sensitive,” said Hatchette.
The two-tier test is the universally recommended approach by the NML, the Canadian Public Health Laboratory Network and the U.S. Centers for Disease Control.
DOCTORS DISAGREE ON BEST TEST
Despite its endorsements, Dr. Ralph Hawkins said he isn’t sold by Canada’s use of the two-tier test.
He said Nova Scotia, and the rest of the country, is turning sick people away by clinging to the current method of testing.
“There’s agreement that this is the standard but it’s a lousy standard,” said Hawkins, a clinical associate professor of medicine at the University of Calgary.
“The status quo is not serving our patient population.”
When asked if there is more accurate testing available elsewhere, Hawkins said the answer is “unequivocally” yes.
He pointed to a single-tier test available commercially in Germany, called the ELISpot, as a solution.
Quoting a study published in Cells, a quarterly journal, Hawkins said the test is able to detect Lyme disease 84 per cent of the time within the first two or three days of the infection.
“If we permitted the use of ELISpot for patients who are infected early rather than the two-tier testing, we would have a far more sensitive way of identifying patients strictly using that approach,” he said.
The test isn’t without its nuances.
Hawkins explained testing accuracy for Lyme disease is broken down into sensitivity or how likely the test is to find the infection and specificity, how reliable the test results are as a true positive.
ELISpot, according to Hawkins, is far more sensitive at picking up early infections than the two-tier test.
But when comparing specificity, Hawkins acknowledged the two-tier test was rated higher than the ELISpot’s 94 per cent.
SOUNDING OFF ON OTHER TESTS
When asked about the effectiveness of other tests — including the ELISpot — Hatchette said nothing has been definitively proven to be better than two-tier testing.
“The data just doesn’t support (ELISpot’s) accuracy and at this point, it is not recommended,” he said.
He also advised against seeking testing through private labs, explaining that many don’t follow approved CDC or Health Canada guidelines.
“They have a lot of potential tests for which there is no data to support how accurate they are,” he said. “You’ve got to remember that these labs are a business.”
Still, Hawkins said failing to explore other options while doubling-down on a test known to poorly detect early infections was a mistake.
“I think we’re constraining ourselves unnecessarily,” he said.
“There are more sensitive ways of doing things with acceptable specificity that will serve the patient population better.”
Hatchette said research is underway to develop more accurate testing methods but for the meantime, the public must rely on current testing and preventive measures.
“When you’re done enjoying the outdoors, make sure you check you and your loved ones for ticks,” he said.
Hatchette said he sympathizes with people who are looking for answers.
“It’s understandable because people are suffering from real and debilitating symptoms and are looking for answers but if your test is negative, you need to look for other causes for your symptoms,” he said.
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