vial with liquid

Let’s say you want a trustworthy Covid antibody test, to establish that you have coronavirus antibodies.

Where should you go? Should you avoid or disbelieve any tests or testing locations? What else should you know? Does a trustworthy test exist? Has the technology improved to the point that we can believe any of the tests?

First, why do you want a test? We have written a lot about how the tests for active infection and also for antibodies (showing presence of a previous infection) are only partly reliable, So why are we coming back to this?

Several reasons: First, I have now had four positive antibody tests and two negative ones. I wrote about it here in this omnibus piece. My conclusion: I had something, probably, and the four “science-oriented” tests I had — New York State Department of Health, Stony Brook University Medical Center (twice) and in a Mount Sinai Health Systems study — are probably more accurate than the two negative ones, at CityMd and Westchester Medical Center. Both of those were done on Abbott Labs technology, I was told. But there’s not a lot of concrete evidence for and against any of the tests. So we decided to take another look.

Second, why do I care if I “had something”? Why should you care? And why should you believe any of the tests?

Increasingly, people with “long Covid” or “post-Covid or “long-haul Covid” or whatever you choose to call it are experiencing downstream consequences well beyond an initial infection. See these support groups: Body Politic Long-Haulers, Survivor Corps on Facebook and its own site, and  the Covid-19 Long-Haulers Discussion Group on Facebook. There are many others.

So it makes sense, if you can get an antibody test suggesting  past infection, to have that information in hand. We wrote about this man who had no diagnosis of Covid, but is now in post-Covid territory (with a negative test for active infection and a positive antibody test). A friend whose son was ill in February but was never tested (because of the testing black hole, and because he did not have what then were considered “typical” respiratory Covid symptoms) says he’s experiencing some unexplained things now, and is “not the same kid.” What if she learned he had Covid back then, and is now “post-Covid”?

Third, people keep asking us where they should go for an accurate antibody test or an accurate respiratory test. It seems like a logical question, and we don’t have answers. Antibody tests are now widely available. But they are not completely reliable. And often it’s hard to find out from the people administering the tests what the brand name is, and where it is being processed. My CityMD test probably used Abbott testing materials, the nurse said, and was processed at Quest, though the answers were a little murky. At Westchester Medical Center, they told me they used the Abbott test and processed it on site.

Fourth, it seems that by this point, with the virus present in the human population for nearly a year, somebody should have come up with a more accurate test. I’m not a scientist and I understand that this is not the same thing as a pregnancy test — yes or no is generally pretty clear — but it seems that the science might have gotten better.

Fifth, because we’re covering this, I have learned that there are people who had much more serious illnesses than I did, and who are deemed “not Covid” for purposes of medical science, since they didn’t get a positive test, either for active infection or for presence of antibodies. Some of them have been denied treatment because they are “not Covid.” Wouldn’t it be ideal if they could actually have “Covid” on their medical records? Did some of them test negative but were actually “false negative”? How would we know unless they took another test?

We should also note that it’s not clear what the presence of antibodies means. No one knows if those antibodies confer any immunity, and if so for how long. If you’re planning to have a test to document that you have antibodies so you can get out of lockdown, don’t.

So we decided to take another look at the testing landscape, specifically for antibodies indicating the presence of a past infection.

Mount Sinai’s reliable test is … unavailable

Outside of the commonly available commercial tests, it is often said in scientific circles that the antibody test from the Mount Sinai hospital system in New York City is one of the most reliable ones. The Mount Sinai website says you can’t get the test there. But you can theoretically sign up to donate plasma, and get the Mount Sinai test as a qualifying event. I signed up to donate, but the process got hung up over the request that I supply written proof of a positive test. I’m still working on that.

Mount Sinai has also chosen to commercialize its technology via a joint venture called Kantaro Bio.

Kantaro partnered with a Minneapolis bio-tech company called Bio-Tecne, which is manufacturing the testing kits. Here’s a joint page on the Bio-Tecne site about the venture. The page says “For Research Use Only. Not for use in diagnostic procedures.”

I asked Kantaro by email where I could get tested or get their kit in mid-November, and the robot response I got said “Kantaro has only begun its journey, and there is much more to come. We will respond to your inquiry as soon as we can. The commercial test kits for clinical laboratories will be available soon. However, in the meantime, the Kantaro team would very much like to understand your testing needs and hear from you. If you would like to provide us with your information, or have a question regarding test kits, please fill out the Intake Form found here

A Bio-Tecne chat robot on the site said, “This test is only available through a clinical lab, where the testing will be preformed. We do not have any current plans to ship to individuals at this time.”

When I asked further what clinical lab offers the test, the chat robot said: “We are not able to provide this sales information. We have jointly developed this kit with Kantaro, their website has the most current information on the clinical testing process.”

Apparently the test will be available soon-ish, judging from this recent news story.

I bought a shipment of antibody tests

In the Mount Sinai study, I tested positive on an at-home rapid test from Elabscience, shown at right. I found Elabscience online and wrote them on Nov. 16, to ask if I could buy 10 rapid test kits.

covid home antibody test

Elabscience was responsive by email (always in the middle of the night.) I did buy a shipment of 40 test kits, the smallest size of shipment, with shipping amounting to a total of $123. ElabScience, it turns out, is based in Wuhan, Hebei, China, the site of the initial outbreak. The tests haven’t arrived yet, but they look pretty much like the one i had in the Mount Sinai study. I also had to pay $40 to my bank for the international transfer.

Will they be accurate or reliable? Who knows?

When I was buying them, I asked the folks at the Mount Sinai study why they chose this particular test.

“At the time we ordered these kits there was not much known yet about the sensitivity/specificity of them since COVID was still so new,” Tess Levy, one of the study coordinators, wrote in an email. “We did some internal validation at our center and also looked at the results from our COVID positive / COVID negative populations in the study.  We found that the sensitivity and specificity is quite high, but again is only validated for research and not for clinical purposes.

“We also went with this company because they were able to produce the stock we needed faster (some other companies had month long delays).  There were a few other options out there but less well-known companies that we were not sure of.”

I also asked Elabscience what other tests they have. They have an antigen rapid test kit to determine presence of an active Covid  infection, but they don’t have FDA authorization to sell that in the United States.

For the antibody test I bought, their representative told me “This product is manufactured by UNscience, a wholly owned subsidiary of Elabscience located in Wuhan, China, specializing in in-vitro diagnostic reagents. And your order will be shipped directly from our warehouse in US.”

Buying antibody tests online

There are any number of antibody tests available online. If you google “covid antibody tests” and limit results to “shopping,” you’ll get something like what is here. But are these reputable and reliable?

home covid anti body testing kits search results

Likewise, you can find a page on listing multiple suppliers of tests for antibodies and for active infection, offering to send you a test kit to your home. Same question, though: Are they reliable? How would you know?

T-cell tests

There’s been a lot of conversation about T-cell detection as a new way of sensing previous exposure to Covid. Apoorva Mandavilli, the New York Times Covid reporter, wrote recently that these tests could be more accurate than the antibody tests — or more meaningful, since the T cells might be more important than antibodies in forming an immune response. Research publicized in early November, though not reviewed for publication, was promising, Mandavilli wrote, citing a new study.

“In the new work, the team analyzed samples from 2,200 people in Vo, Italy, which tested all 2,900 of its residents for presence of the coronavirus in March, when cases were soaring there, Mandavilli wrote. “The researchers’ test, called the T-Detect, correctly identified 97 percent of those who had a confirmed diagnosis, compared with 77 percent from a commercial antibody test called DiaSorin.”

This T cell test is not commercially available. DiaSorin is based in Saluggia, an Italian town in the Piedmont region. The site also says the Liaison test needs to be performed with Liaison technology, and some U.S. testing sites use it.

So what is the best testing strategy for an antibody test?

First, why do you think you need it? Assess the facts carefully.

Second, what test? The Abbott test was much praised in the spring. But there has also been a lot of reporting about how the Abbott test might be inaccurate because it set its detection level high — perhaps as a result of using very ill patients’ antibody levels for the development of its test.

That might be what happened to me: The Abbott test did not “see” my antibodies because I didn’t have a lot.

It’s probably preferable if possible to take a test that’s not just binary — yes or no — but includes levels of antibodies, like the ones I had at Stony Brook as part of their convalescent plasma donation study assessment.

They told me I had antibodies, but not enough to make the therapeutic levels their scientists wanted. That might be a “weak positive,” but still a positive.

My next steps: I’ll report on what we learn with the ELabSciences tests.

I’ll be getting in touch with Northwell Health and also Quest and Labcorp to see if I can specify that I want a Roche test, a DiaSorin test or an Euroimmun test. When I went to CityMD, I was not able to specify which test I got.

New York City’s testing program, which is free to residents (I’m not a resident), is using the BioReference lab, which our partner Gothamist said earlier this year is using the Roche test.

They said Quest is using Abbott, Euroimmun, and Ortho-Clinical Diagnostics.

Northwell, Gothamist said, is using Abbott, Roche, Ortho-Clinical Diagnostics and DiaSorin.

Jeanne Pinder

Jeanne Pinder  is the founder and CEO of ClearHealthCosts. She worked at The New York Times for almost 25 years as a reporter, editor and human resources executive, then volunteered for a buyout and founded...