My search capability stinks, so I thought that maybe someone can help. I was trying to find some of the posts discussing the Labcorp limits on the SARS Spike Ab test. I know that there has been some modification recently in the way Labcorp is reporting the results.
The reason I'm asking is that after a summer bout of Covid and an Evusheld shot about 1 1/2 months ago, I wanted to see where I shook out so I had the test done.
Nucleocapsid results were negative, not surprising, since it tells me that my own body didn't produce any antibodies as a result of the Covid infection.
The Spike Ab was 250, a good number which, I believe, is the result of the Evusheld shot. I just can't remember if 250 is a powerhouse number or barely scraping by. I thought that I recall some discussion that the new testing limits were going as high as 2500 but I can't recall and I can't find the discussion.
Any help is appreciated.
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hhk50
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hhk50, Here's what I believe to be the case with Labcorp's reporting range for the SARS-CoV-2 Semi-Quantitative Total Antibody, Spike assay:
Before May of 2021 the highest antibody titer reported was >250 U/ml. In May of 2021 that was changed to >2500 U/ml; in March of 2022 highest levels reported were changed to >25,000 U/ml.
To give you an idea how your post-Evusheld antibody titer compares with 5 other individuals, I’ve posted data from a clinical trial that included measuring anti-spike antibodies post-Evusheld. At the time this study was done the dose of Evusheld was the 300 mg dose which has since been changed to 600 mg, which probably would have doubled the antibody titers.
In the 5 individuals for whom this data was reported, the increase in antibody titer attributed to Evusheld ranged from 195 to 1,290 BAU/ml. There was no discussion of the ~6 fold difference in titers among individuals. The BAU units in these plots are roughly equivalent to the U/ml that Labcorp reports. (U/ml equals 0·972 BAU/ml)
7 months ago Health50 reported a Labcorp post-Evusheld antibody titer of 2227 U/ml two weeks after receiving the shots. healthunlocked.com/cllsuppo...
Serum neutralization of SARS-CoV-2 Omicron sublineages BA.1 and BA.2 in patients receiving monoclonal antibodies Nature Medicine 23 March 2022 nature.com/articles/s41591-...
Plots showing titers of Evusheld antibodies in serum from five individuals.
Thanks for the informative reply. I'm going to wait another month, post Evusheld, and retest at a different Labcorp. It's possible that they nailed the antibody level exactly at 250 or, more likely, they are just sloppy in the way they report the results. I appreciate your help.
Hi hhk50 - Curious, did your spike Ab results say > 250 U/ml? If so, the LabCorp lab you used may have still been using that as their “max” score.
On the other hand, I’m in the LLS Ab Study and have seen LabCorp max scores go from >250 to >2500 and now >25000 U/ml at the test site I use about every 2-3 months.
Yes, it possible to register >25000!
So now you may be wondering, if indeed you got a >250 “max” score, how much greater is it? You might try calling other LabCorp test sites and ask them what their max scores are n if say it’s >25000, then suggest get retested to see where you really land on the Ab scale. Just an idea if that interests you.
But hey, congrats on your score, it appears to be a good one! Hope my max scores explanation has helped.
Thanks for your reply. Yes, this was part of the post-Evusheld LLS study and they reported the result as exactly 250 with the word "Positive". I'm starting to think that they were simply sloppy in the way that they report. Either way, as you mention, it appears to be a good result.
Even though they collected my insurance info at the blood draw, I have not been billed yet, nor did they collect money at the web site. I believe the cost is something like $45.
As others have noted, there are no studies showing a correlation between particular scores and particular levels of protection from infection, symptomatic disease, hospitalization, or death since the original study of Alpha and Delta variant patients.
On the LLS vaccine study, I myself had 3 Pfizers, with a max of 4.7U/mL, then a Moderna half dose showed 85 U/mL. I then got Evusheld 1/2 dose (the original dose), in February, followed by the second half dose on May 9.
On May 16, I got my first COVID symptoms, and was antigen positive, likely BA.2 based on local prevalence. I did Paxlovid, scored antigen negative a day after the last dose, but got lighter symptoms a few days later, and was antigen positive again. I continued with symptoms, and got culture that showed a bacterial infection, plus slight antigen positive at day 21.
I will be getting a booster soon. Not sure which one yet. But I've already tested spike Ab, for what it's worth. I was at 555 U/mL on September 14. But my Evusheld dosage was split by 3 months, and I was beyond 6 months from my first half dose
On June 15, I had scored 3150 U/mL a month after 1st symptoms, and 5 weeks after 2nd half dose of Evusheld. That seems in line with scores I've seen from some other people who got Evusheld alone, though some scored between 2000 and 3000 U/mL on LabCorp.
I say all this to convince people to continue masking. Vaccinations and Evusheld will not prevent infection for most of us, though it may keep us out of the hospital or the morgue. The pandemic may be over for normal people, but it's not over for us. A well fitted N95/KN95/KF94 mask is probably worth multiple doses of vaccine and Evusheld.
Best of luck,
=seymour=
A clip of my latest test for comparison to your test report:
Thanks, Seymour. After reading your note, I relooked at the various tests and think that I'm getting a better picture. Let my engineering mind lay this out bullet form -
1) I had a 1/2 dose of Evusheld back in April at a county clinic in nowheresville because my own hospital was on Evusheld allocation. The tiny clinic thought they were giving me a full dose, as did I, but I later found out it was only a 1/2 dose.
2) I contracted Covid in June, and recovered after about six weeks. I went for a Semi-Quant Total Ab the end of July and got inconclusive results. However, I see today when pulling up that test in the Labcorp site that it shows a value of 299 for the spike protein reading. (That's after the 1/2 dose of Evusheld).
3) I then had a full dose of Evusheld in mid-August. (So - this makes it 1 1/2 doses of Evusheld
4) Last week I took another Semi-Quant total Ab and got the result of 250. I think that the fact that it was 250 threw me because it is such a "round number", but I suspect that's where I am. Better than nothing but not overwhelming.
At any rate, I'm thinking that I better put my mask back on.
I had 2 antibody tests by LLS @ LabCorp in '21. Similar results. After 4 VAX's, talked doc @ a university med center into an antibody test, to include Chain Blocking. Look at adding this, id your doc knows what it is. My results were I was basically unprotected, then got IG tests (low) to build a case for Evusheld. Expect to repeat tests as I get close to 6 months post-Evusheld & refrain from 5th VAX.
Good assessment. Let's hope enough EVU, Paxlovid, etc., is still available. Gov't bought limited amount early this year, but no more $ allocated to buy more.
My Labcorp antibody status was 196 at the 5 month interval. I am going to receive my second round of Evusheld next week. (w/o Sept. 25th) Hope this info helps.....
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