4 January 2022 (Tuesday) - Sample Quality


Oh I got so cross as I listened to the news on the radio this morning.  Elizabeth Holmes, founder of supposed blood testing firm Theranos, has been found guilty of several charges – including conspiracy to defraud investors. Did it really need a high profile court case to prove this?
Wasn't it screamingly obvious that what she was claiming just wasn't feasible?
I thought she was on the fiddle from the moment I heard about her business as did pretty much everyone who knows the first thing about blood tests. Her company had this plan that they would send out a blood testing kit to whoever would pay for one. You would stick in a few drops of blood, and their kit would tell you all about the state of your health. Sounds too good to be true doesn't it? Now I might now a tad more than most about the subject, but in its simplest terms any sort of test (be it blood or anything) is only as good as that which it is testing. You need a decent sample for blood to get a good result. To get a good sample of blood for most purposes you need to stick a needle in a vein. You can't get it from a few drops nervously squeezed from the end of your thumb. Have you ever had a blood sample taken? Look at the colour of the blood that is in the bottles collected from a vein and compare that to the colour to what you see when you cut yourself. *Completely* different!!

Or take the UK version of this which is all over the telly adverts at the moment. The company offers all sorts of medical testing, and claim they won't make a charge if they don't find anything wrong. What a nice little earner(!) With people taking their own (frankly dreadful) blood samples we have *incredibly" poor quality blood being tested. Obviously the results are going to be squafty. And so the company gets their money as they have found something wrong.
And a terrified public goes running to their GP who does a proper blood test and finds all is fine.

It's not unlike the terrible reputation the lateral flow tests for COVID-19 are getting. So many false negatives? Is that the fault of the test kit or the fault of that which they are testing? How far up your nose do you shove your swab?

Yes I know all about diabetic finger-prick testing and can bore you extensively about why that is the exception that proves the rule! Or perhaps my loyal readers (of which I seem to have quite a few !) might like to explain this as a form of CPD of your own...

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