Coronavirus antibody tests

[animist]

there are plenty of recovered cases of PCR confirmed infections and typical symptoms but no antibodies at all.

The selected quotes below are copied from Humoral immune response and prolonged PCR positivity in a cohort of 1343 SARS-CoV 2 patients in the New York City region research article published on April 30, 2020.

Respondents self-reported date of symptom onset, date of positive SARS-CoV-2 test (if applicable), and last date of symptoms. Duration of symptoms was calculated from these self-reported dates.

We measured serum IgG antibody titers using a serologic enzyme-linked immunosorbent assay (ELISA) developed at Icahn School of Medicine at Mount Sinai and described on March 18, 2020; this serum test has a sensitivity of 92% and a specificity >99%.

We measured SARS-CoV-2 antibody titers in 1,343 people over the first three weeks of the survey (March 26, 2020 to April 10, 2020) using a now FDA approved two step ELISA.

47% had confirmed SARS-CoV-2 diagnosis by prior PCR testing.

In contrast to some of the prior literature on formation of antibodies, over 99% of the patients
who self-reported or had laboratory documented SARS-CoV-2 infection developed IgG
antibodies using our assay. Additionally, our findings suggest that IgG antibodies develop over a
period of 7 to 50 days from symptom onset and 5 to 49 from symptom resolution, with a median
of 24 days from symptom onset to higher antibody titers, and a median of 15 days from symptom
resolution to higher antibody titers.

Of the 113 participants with PCR confirmed SARS-CoV-2 and weakly positive or negative titers
on their first serum antibody test, 64 have returned for follow up antibody titers at the time of
submission. Of these, 57 (89%) displayed increased titers between the two tests, a median of 13
days (5-25) later (Figure 1B). Four remained weakly positive, and three remained negative.

The three that remained negative all self-reported positive PCR testing (none were documented in our EMR).

[FinlandGirl]

Your claim was that there would be no exceptions at all.
Therefore 1 exception is sufficient to prove that you were wrong.

Exactly, could you be so kind at the second time of asking to share a valid and trustworthy proof that such an exception exists?

https://www.medrxiv.org/content/10.1101 ... 2.full.pdf

Could you imagine any explanations of these still presumptive exceptions?

I already gave you a plausible explanation:

A good innate response without activation of the adaptive immune system would be a plausible explanation, and would imply no immunity for these people.

Other explanations are possible (some are mentioned in this paper), truth is that that details of the immune response to COVID-19 and related topics like immunity are still very poorly understood.

[mois_2012]

Here you can do the antibody tests

"The price of the finger-prick antibody test is EUR 59 (incl. the test to confirm a positive result), also in connection with taking a sample from the nasal cavity."

https://www.mehilainen.fi/en/coronavirus/antibody-tests


"The test requires a referral issued by a physician and can be performed three weeks after the possible coronavirus disease, at the earliest. When you have received a referral, you can book a sampling appointment directly from the clinic by calling Terveystalo’s customer service at 030 6000 or by booking an appointment directly online (starting in week 20). The price for the test is EUR 89 and it is Kela-reimbursable. The Kela reimbursement is EUR 5 and the price after the Kela reimbursement is EUR 84."

https://www.terveystalo.com/en/Occupati ... rveystalo/

As you can see that you will need to get a referral issued by a physician from the clinic (mehiläinen or terveyestalo) from which you want to do the test. To get a referral you will need to pay (mehiläinen: 32-41€ or terveyestalo: 40-65€) as well.
You will need to make an appointment over the phone.

Good luck.