Expensive DNA testing kits with little clinical value will soon have to meet more rigorous performance standards
The “wild west” environment of commercial genetic testing may be drawing to an end with a TGA crackdown coming into effect next month.
According to Andrew Somogyi, professor of clinical and experimental pharmacology at the University of Adelaide, the accuracy of some direct-to-consumer genetic testing was not up to par, and the interpretation of results ambiguous or misleading.
Genetic tests developed in Australia will soon have to be accredited by the National Association of Testing Authorities as well as meet performance standards set out by the National Pathology Accreditation Advisory Council.
These new regulations, which come into effect in July only apply to Australian companies, prompting public health expert Associate Professor Ken Harvey to recommend doctors advise their patients not to buy overseas tests.
“Patients should also discuss the usefulness of locally promoted tests with their doctor before paying for a test,” he wrote in an Australian Prescriber editorial.
Direct-to-consumer testing has been under fire for being expensive, providing limited clinical value and exaggerating the benefits of the tests in their advertising.
Last year, the Australian Competition and Consumer Commission investigated direct-to-consumer gene testing, concluding some advertising “risked conveying a false or misleading impression regarding the usefulness of the test and the consumers for whom testing may be appropriate”.
Chemmart agreed to change its promotion of the “myDNA” service, which was billed as a “revolutionary” test, saying “70% of people who take a myDNA test have a finding that could affect current or future medications”.
The pharmacy charges patients $149 for a full suite of pharmacogenetic tests, and $99 for another report which gives personalised diet and exercise recommendations based on each patient’s genome.
Professor Somogyi said it was likely that consumers were getting inappropriate testing, pointing to companies that advertise drug metabolising enzyme tests that overstated the number and types of drugs that were likely to be affected.
So far, the evidence was strongest for gene testing to determine drug toxicity, rather than whether it would work or not, Professor Somogyi told The Medical Republic.
Instead, factors such as age, weight, drug interactions, adherence and renal and liver function were just as important as gene variants in determining how the patient responded to medications, Professor Somogyi said.
There is also the concern that direct-to-consumer gene testing fragments care.
Professor Somogyi said pharmacists needed to be very careful about continuing to provide and promote these tests.
“To some extent they might have a conflict of interest as well, because they might be getting paid for the service,” he said.
“If a person came to them [asking for a test] then I think the duty of pharmacist would be to contact the GP,” Professor Somogyi said. “Bringing the GP and specialist into the process is important.”
Simply standardising the tests did not go far enough, according to Professor Harvey and Dr Somogyi, who are calling for better education of all health professionals as these tests become more common.
It was time for a group such as the NHMRC to step up and provide patients and consumers with education, and keep education independent of companies associated with the tests, Professor Harvey said.
Professor Somogyi agreed, saying an “overarching regulatory framework involving national regulatory bodies, with advice from professional societies, is needed to resolve critical issues”.
Specifically, clinicians needed advice on what variant alleles should be tested, and how to interpret the test, with guidelines on how to change the drug or dose in light of laboratory results, he said.
For example, a company might send a GP a report which only states that the patient has genotype CYP2D6*4/*4, simply writing “poor metaboliser”, Professor Somogyi said.
A 2012 study by Murdoch Children’s Research Institute found only 7% of genetic specialists said they would be confident interpreting and explaining the results of these tests.
The current system also saw these results and interpretations vary between laboratory to laboratories, he added.
“A national regulatory system including standardised reporting and guidelines for interpreting test results is urgently needed,” he said.
Aust Prescr 2017; online 1 June
