In the same old very flogged very dead horse language, we now have yet another game changer in the fight against covid–19. Quite how a fight against a pandemic came to be a game passed Dr No by, unless it has something to do with the MP for Newmarket, Hatt Mancock, being partial to a flutter on the horses, and the chief pongo for the time being at NHS Test and TitsUp, Dido Make-me-a-Cherry Harding, also having a bit of thing for the horses. In any event, according to a DHSC press release, millions of oven ready DIY swab-to-smartphone 90 minute covid–19 tests are to be made available over the next few months, allowing widespread community covid–19 testing on an unprecedented scale. As the modern idiom has it, what’s not to like?
Well, just about anything. Two tests from two separate university linked start ups are on the grid. The larger package — 5.8 million tests for £161 million — has been piggybacked onto a doughnut counting DNA sequencing diet and health app-cum-thingy called DnaNudge — totes Siobhan Let’s nail this puppy to the floor Sharpe naming here — that claims it can profile your genome and tell you which lemon to juice. The second smaller package — only 450,000 tests, cost TBA — is a dedicated SARS-CoV-2 test called LamPORE.
We’ve been here before. Back in April, and then June, we had the game changer SAMBA II, a similar near patient rapid test kit for SARS-CoV-2. Unlike DnaNudge (Imperial College, London) and LamPORE (Oxford), SAMBA II’s Cambridge based developers did publish two pre-prints reporting sensitivity and specificity, but with standard lab based RT-PCR testing as the reference test, which we already know is far from perfect. Nonetheless, SAMBA II’s performance wasn’t a million miles away from the standard test, with 97-99% sensitivity and 99-100% specificity (Dr No never likes 100%. What’s the Confidence interval? 98-102%?).
The curious thing is, since around the middle of June, there has been effectively no new mention of SAMBA II anywhere, apart from a mostly Thai authored systematic review and meta-analysis pre-print dated 11th July 2020 which concluded that SAMBA II had ‘good diagnositic performance’ (this was based on the previous two pre-prints), and a WHO report dated 14th July 2020 which lists SAMBA II as ‘awaiting submission’, for review and assessment. Perhaps the real world changed the game for the game changer? Or perhaps there are hundreds of SAMBA IIs out there beavering away in back rooms? Who knows — or cares? Even the manufacturers appear to have dropped the dead pony, having stopped promoting their product some time ago.
Rather than drill multiple holes in the DnaFudge — tempting to get going on do you really want Track and TitsUp to ‘accidentally’ get your DNA profile, but will leave that to one side — and LamPOON products, Dr No is simply going to point out that neither of the developers for these products has released proper data on sensitivity and specificity. DnaFudge claims that ‘trials comparing COVID Nudge against several NHS laboratory results indicated 98% sensitivity and 100% specificity’ — that 100% again — while LamPOON, as of 30th July 2020, is still ‘in the validation phase’.
Putting aside the real world problems with DIY testing — Richard Smith, a doctor and past editor of the BMJ gives an account here — Dr No accepts that it is entirely possible that one or both of these products, either or both of which may be able to use saliva rather than a more tricky swab sample, may one day turn out to have a real word use, even if the history of covid–19 testing is littered with corpses of game changers that passed out before even completing the first lap. That doesn’t alter the fact that, to date, neither of the new DSHC tests has published data demonstrating adequate sensitivity and specificity. ‘Trials…indicated’ in a press release is a fudge, while plugging a test that is still ‘in the validation phase’ is not a million miles away from making a lampoon of reality. Hatt Mancock may be ready to back both of these horses with hundreds of millions of public money, but to Dr No, that looks precious like smoking the wrong mackerel.