I cannot find clear explanation of the meaning of a 71 on antibodies test result….yet it is listed as ‘high’? can someone tell me? Thanks!

[ChattahoocheeBoy]

Can anyone tell me what an antibodies test result of 71 means? Quest rated 71 as high??

[Robbie_W]

No one knows for sure. The best response is >2500. The worst response is 0.

[ChattahoocheeBoy in reply to Robbie_W]

Thanks for responding. It was confusing for a 71 result to be considered high!

[Patc890USA in reply to ChattahoocheeBoy]

My result said >20 HIGH

[Vlaminck]

Hey, ChattahoocheeBoy -- I enrolled in a test of CLL and third booster vaccine response. They did a quantitative on me after and I was 11.5, which the study coordinator told me my oncology nurse said was terrific (terrific generally or terrific for CLL, I don't know). That same study coordinator told me that after one reaches 30 they stop counting. In this framework, yes, you'd clearly seem pretty darn high. But is my figure and the 30 they stop counting after on the same system of counting as yours? That is what I don't know. I am in US (originally from Chattahoochee country, BTW). I suspect we are both obviously in a different system from any that has numbers like >2500 as a score, as RobbieW mentions, esp if they stop counting at 30.

[gardening-girl]

As Vlaminck suggested, it would be important to know specifically which test you had, because the range depends on the specific Quest test, as well as the specific equipment and reagents as shown below.

The Quest web page lists three two different tests as shown below. The range for the SARS-CoV-2 Total Antibody, Spike, Semi-Quantitative immunoassay test has a rage of 0.4-2500.0 U/mL whereas the range for the SARS-CoV-2 semiquantitative IgG test differs depending on the equipment and reagents used.

Test 39820 The result of the SARS-CoV-2 Total Antibody, Spike, Semi-Quantitative immunoassay test is reported as positive at an index of (analytic measurement interval of 0.4-2500.0 U/mL)1.

1. Cobas® Elecsys Anti-SARS-CoV-2 S (spike). Instructions for use. Roche Diagnostics Inc; 2021. Accessed October 6, 2021. fda.gov/media/144037/download

A SARS-CoV-2 semiquantitative IgG test result is interpretated as a positive value at an index of ≥1.00 (analytical measurement interval of 0.50-150.0 and 0.5-100.0 for Siemens Atellica2 and Siemens Centaur3, respectively).

2. Atellica® IM SARS-CoV-2 IgG (COV2G; spike). Instructions for use. Siemens Healthcare Diagnostics Inc; 2021. Accessed October 20, 2021. fda.gov/media/146931/download

3. ADVIA Centaur® SARS-CoV-2 IgG (COV2G; spike). Instructions for use. Siemens Healthcare Diagnostics Inc; 2021. Accessed October 6, 2021. fda.gov/media/150238/download

questdiagnostics.com/health...

[mickimauser11]

Important is also the quality of the antibodies not only the number

[LeoPa in reply to mickimauser11]

How do you measure the quality?

[HopeME in reply to LeoPa]

My Nurse Practitioner said to send her the results and she would help interpret although as others have said nothing is back and white with these tests.

[gardening-girl in reply to LeoPa]

LeoPa, the antibodies which are measured by the Total Antibody, Spike, Semi-Quantitative immunoassay tests are called 'binding' antibodies because they bind to the Spike protein. However, just because they bind somewhere on the Spike protein doesn't mean that they block entry into the cell. Antibodies that block entry are called 'neutralizing' antibodies. The detection of neutralizing antibodies is more complicated and thus more expensive and time consuming. The Total Antibody tests measure binding antibodies, only a portion of which would be neutralizing. The neutralizing antibodies would be considered to be of higher quality, since they can actually block viral entry, hence block infection.

[LeoPa in reply to gardening-girl]

Thank you, I learned something new again

[Pin57 in reply to gardening-girl]

Thank you G-G for all your very knowledgeable replies regarding antibodies … one question: so if one has a high number of spike (binding) antibodies (e.g., in the thousands), would that likely correlate to a higher amount of the coveted neutralizing (viral blockers) antibodies?

[gardening-girl in reply to Pin57]

In general I think that yes, higher total binding antibodies would mean higher neutralizing antibodies. There are quite a few correlation of protection papers that plot Anti-Spike antibodies and neutralizing antibodies, but I've never seen a paper report what fraction of total antibodies were neutralizing but the data probably exist somewhere.

Most publications report that the level of neutralizing antibodies correlates with risk of infection, ie higher neutralizing antibodies-lower infection rate. Some publications report a strong correlation between total binding antibody levels and neutralizing antibody levels. Others find a lower correlation as reported below.

Read on if you dare.

This is one of the latest articles looking at both binding and neutralizing antibodies:

SARS-CoV-2 mRNA vaccine induces robust specific and cross-reactive IgG and unequal neutralizing antibodies in naive and previously infected people

Cell Reports February 01, 2022

cell.com/cell-reports/fullt...

•Healthy naive and infected subjects develop robust spike IgG after full vaccination

•After the first dose, one-third of previously infected subjects lack neutralization activity

•Neutralizing antibodies are variable in previously infected and naive subjects

•Neutralizing antibodies against Delta variant are weaker than the reference strain

Another paper:

“First, trials of several vaccines (AstraZeneca, Moderna, Pfizer) have shown substantial efficacy following the first dose despite low neutralization titers, with many subjects with titers from the pre-dose two sample below the lower limit of quantification. This suggests either relatively low neutralization assay sensitivity or non-neutralizing antibodies and T cell responses may be functionally important, which is supported by the evidence that binding antibody titers appear robust at the same post-Dose 1 time points, and that Fc functional antibody responses play a role in recovery from natural infection and correlate with protective efficacy.”

Evidence for antibody as a protective correlate for COVID-19 vaccines

Vaccine July, 2021

sciencedirect.com/science/a...

One thing to keep in mind is that the term “binding antibodies” can be used to mean two different things. The way I am using it is in reference to all antibodies that bind to the spike protein, including neutralizing antibodies. Sometimes the term is used to mean the antibodies that bind, but don’t have neutralizing ability, ie binding + neutralizing = total.

[Pin57 in reply to gardening-girl]

Thank you for another awesome reply explanation!

[gardening-girl in reply to Pin57]

Pin57, I found an additional paper today of data showing a correlation between anti-Spike IgG and neutralizing antibodies post vaccination.

Quantitative analysis of mRNA-1273 COVID-19 vaccination response in immunocompromised adult hematology patients

Blood Advances Feb. 2022

ashpublications.org/bloodad...

“Obtaining S1 IgG >300 binding antibody units (BAU)/ml was considered adequate as it represents the lower level of S1 IgG concentration obtained in healthy individuals and it correlates with potent virus neutralization.”

BTW, 300 BAU/ml = ~ 298 U/ml

Plot of Anti-S IgG vs Neutralizing antibodies

[Pin57 in reply to gardening-girl]

Interesting n very recent it is.

Graph clearly shows a linear progression (n correlation) and the article did note the expected exceptions.

Thank you for sending.

[mickimauser11 in reply to mickimauser11]

They can Check in a clinic this was suggested by an immunologist Dr. Mustafa from Rochester a presentation by the los.org on YouTube

[DriedSeaweed]

Don't compare quest and labcorp numbers directly. My quest was around 66 but labcorp a couple thousand. They were taken relatively close together. As mentioned above each test may go by different scale.

[TruthJunkie]

Yeah, ChattahoocheeBoy, being isolated as we are out here (and I am on Oahu), I would really think 1000 times over before moving to Hawaii, in general, let alone with CLL. I moved here in 1976, and being young, had no clue what my medical needs might become, going into the future. You have far more facilities closer to you, no doubt, than we do here…especially on the Neighbor Islands. Best wishes.