#MSCOVID19. GloSlow… Antibody tests

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Testing for COVID-19 in the UK has been woefull. It is too little too late and sadly now many of us will never know if we have been infected or not. I admit I am embarrassed by the speed that we have have been able to act…Wow getting you hands on human samples is even more tedious that working with animals. I will stop there in case I get myself into trouble

I am being tested for virus particles as part of a some National survey and am getting swabbed every week and as a consequence am getting my shopping paid for as they are giving me vouchers to participate….Maybe in the hope that I go out and spend it and get infected in the process…Bonkers. What a waste of public money. I wonder if anyone has barfed, whilst doing this I gag as I tickle my tonsils every week.

Problem in my mind they have made a mistake and did not test me to see if I have or had antibodies and so we dont know if I was infected. If I get infected they will test anitobodies but would that be a primary or secondary effect.

Antibody testing should have been done months ago, but it has become a weeing contest and it is “mine is better than yours” meaning nothing gets done. I guess most of us would like a “yes” or a “no” over whether we have been infected. The weird thing is that the Universities advising the government that the competitiors products are crap are the same universities that are trying to sell their test to the government and people within those universities are possibly lining their pockets on the back of national interest.

Share price of Diagnostics company that are involved in the UK effort

What happened in April 2020?

However, I have given my blood to NDG and Dr Angry for antibody testing but they wont tell me anything for 6 months, as it is a study.

Maybe I should pop down to Wonderdrug and get it done? There are at least two SARS[COV-2 antibody detection testsd approved in UK. The first were a Roche test and an Abbot test. There is another one from Euroimmune against Spike protein doing the rounds but I will talk about that one another day. The Roche test appear to come out with a figure and if you are below 1 you are negative and above 1 positive. We got a rip roaring test that was just over a hundred, in our test I think that on came out about in the millions. Don’t add antibody and its about 700 light units.

However, what does the Roche test mean? Maybe some of our readers can enlighten me, as I am abit dense. Based on the pictures on the Roche website. The Roche test is robotic. They have made a SARS-CoV-2 nucleocapsid protein from SARS-CoV-2 and labelled it. One bit with a detection label that gives a signal when stimulated and another nucelocapsid protein that can be pulled on to an electrode to aid washing and then allow detection and making it robotic.

This is the assay according to the website

So I am having problems picturing this. This will detect IgG but also IgM and IgA. IgG has two binding sites, IgA has four and IgM has 10 so if a biotin and a ruthenylated molecule binds to antibody it is detected by biotin molecules that is captured and the ruthenylated bit gives a signal. But surely if two biotin (grren) molecules bind it is captured but is not detected and if with two ruthenylated molecules (Red) it gets washed away. So by chance you only detect a third of the possible antibodies. Now is one IgA molecule the same a three IgG or one IgM the same as nine IgG molecules or one IgM molcule the same as between 1 and 9 IgG molecules. So what does the quantitation mean?. Maybe some bright sparks can tell me. I guess its important as this is the basis of a diagnostic test. A yes/no answer I undertand but a level. Whats does this mean?

Samples in black boxes are not detected

In the case of the GloBodies every thing is in excess of the antibody molecule so and IgG would get 2 tagged antigens, IgM would get 10, IgA would get 4 and all the antibody would be captured. The output is linear, but in the scenario above two IgM molecules could have two tag molecules or anywhere between 18 and the IgM,A and G is not confused as you assay separately or not if you just want a test yes/no answer

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MouseDoctor

14 comments

  • When I had my NHS antibody test, they asked if I’d had a temperature and a cough on the form, a yes or no answer.

    I didn’t have these but did have other symptoms, though they didn’t ask to state them. I felt they missed an opportunity there.

  • It could be worse. There are many other ways of mismanaging the testing process. Here in Jersey the glimmer of light is that some of us have been antibody tested. RNA screening for active infection is offered every four weeks. The screening is sufficiently spaced that you could become infected, spread the infection and recover without being tested during the infection period. This means that contact tracing fails at the first hurdle. Environmental Health have taken charge of the testing, so you have to cancel appointments (reducing practice income) and go out of your way to attend. Environmental Health didn’t have sufficient staff, so they recruited unqualified staff to cope with providing this inadequate service. Not even GPs are trusted to do this simple test that people in the UK are performing on themselves. This is not mandatory and no inducements are offered. Testing is by throat swabs instead of nasopharyngeal swabs, halving the likelihood of detecting infection in an infected individual and meaning that for every case detected, there are 2 missed infections.

  • ‘The weird thing is that the Universities advising the government that the competitiors products are crap are the same universities that are trying to sell their test to the government and people within those universities are possibly lining their pockets on the back of national interest.”

    Isn’t this what is commonly known as a Conflict of Interest?

  • An unrelated comment. MD can you please suggest a textbooks to start learning and studying immunology, please? An entry level book and another more advanced would be perfect. If there is something propedeutic to learn, could you please advise as well? I became very curious and interested in the subject reading this blog and papers. Thank you in advance.

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