15 August 2020 | New Scientist | 7THE UK government has
announced that two 90-minute
tests will, between them, provide
more than 6 million coronavirus
assessments to individuals at
care homes and National Health
Service hospitals across the UK.
But while the companies behind
both tests say they have validated
their accuracy, the details haven’t
been published. “I’d never heard
of these two tests,” says Jon Deeks
at the University of Birmingham,
UK, who has been comparing the
evidence behind a range of rapid
tests to diagnose covid-19.
One of the tests was developed
by DnaNudge, a company that
offers diet-based shopping advice
for customers who share their
DNA. The coronavirus test is based
on a nasal swab, which is inserted
into a disposable palm-sized
cartridge. Up to 12 cartridges arethen put into a machine the size
of a shoebox, where a chemical
reaction converts the virus’s RNA
to DNA and copies it. Chemicals
seek out sequences from the
coronavirus to signal its presence.
The cartridge system was
developed for retail, but it was
“very simple” to adapt for the
coronavirus, says Chris Toumazou,
co-founder and CEO of DnaNudge.
The second test, developed by
Oxford Nanopore Technologies,
requires a lab or dedicated clean
room for processing samples and
feeding them into a machine the
size of a desktop computer. The
machine handles 15,000 samples
per day, says a spokesperson for
the firm.The spokesperson wouldn’t give
the results of trials, or how accurate
the test is when compared with
standard tests. They told New
Scientist^ that accuracy data is
being prepared for publication.
Looking at data published
before June, Deeks and his
colleagues have identified only
two rapid tests that have been
assessed in independent studies:
the Xpert Xpress test developed
by Cepheid and Abbott’s ID NOW
test. The team is due to publish its
findings soon, but more research
is needed, says Deeks. Most of
the tests seem to work well when
samples contain a lot of virus, but
perform poorly when faced with
low viral loads, for example.Two rapid tests for the coronavirus will be rolled out in the UK, but
neither is supported by published data, reports Jessica HamzelouRapid tests questioned
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newscientist.com/coronavirus-latestWhen asked why the UK
government chose the DnaNudge
and Oxford Nanopore tests, a
spokesperson for Public Health
England (PHE) stressed that it
doesn’t validate or regulate tests.
The spokesperson said PHE would
have “been in the room” when the
decision was made, but didn’t
have the final say. They weren’t
able to comment on the Cepheid
or Abbott tests before publication.Toumazou says that his test has
been validated. His team has been
testing the diagnostic alongside
standard NHS tests at English
hospitals for the past two months,
he says, and has shared the results
with PHE and the UK’s Medicines
and Healthcare products
Regulatory Agency. The MHRA told
New Scientist that DnaNudge has
an exceptional use authorisation,
meaning the tests are allowed to
be used clinically until October,
but didn’t comment on the
accuracy of the tests. PHE wasn’t
able to respond to questions about
accuracy before publication.
The DnaNudge test’s user
guide states that it has 97 per
cent sensitivity and 100 per cent
specificity, meaning that 3 per
cent of cases would be missed,
and there were no false positive
results. These figures are based
on a study of 401 nasal swabs,
40 of which were excluded due
to invalid results, states the guide.
Both tests are promising,
but without detailed, published
results they cannot be properly
scrutinised by the academic
community, says Deeks.
Muhammad Munir at the
University of Lancaster, UK,
whose team has developed a
separate, 30-minute diagnostic
test for the coronavirus, agrees.
New technologies need to be
properly assessed, he says. ❚A billboard in Manchester,
UK, promoting testing
for covid-“Both tests are promising,
but without published
results they cannot be
properly scrutinised”