Antibody testing for SARS-CoV-2: “We need to talk more about it”

Jeremy Booth, DTI

Thu. 18 June 2020

share

save

LONDON, UK: Despite dental settings presenting a significantly elevated risk of infection for those in and beside the chair, testing patients for the SARS-CoV-2 virus remains optional. Those advocating for testing say that it would help to keep dental practices safer, to reduce the amount of personal protective equipment (PPE) that clinics use, and to streamline appointment scheduling and treatment. A number of options are available, and one UK doctor is advocating for antibody tests for dental practices.

Some dental practices are testing patients for the virus before they undergo an aerosol-producing procedure (AGP). Internationally, however, this remains optional. In the city of San Francisco in the US, for example, it is strongly recommended that dental patients undergoing any AGP be tested for SARS-CoV-2 via a reverse transcription-polymerase chain reaction (RT-PCR) test within seven days prior to the procedure. In the health directive from the city, which was updated on 15 June, it is stated that this “test should be performed as close to the day of the AGP as possible.” And that, “this test is in addition to the screening requirements on the day of the scheduled procedure.”

Many readers will agree that this guidance raises as many questions as it answers: if a patient passes the screening requirements but could be asymptomatic, could they not have already had the virus weeks or months before without presenting symptoms? Will a rapid point-of-care test that detects viral activity—such as a PCR test—provide a dependable result? And is it practical to ask patients to self-isolate until the day of their appointment if the test is not conducted on-site? Dr Priya Suaris, medical director at UK company Salubritas, which is offering guidance on SARS-CoV-2 rapid testing and PPE to medical professionals, says that serological, or antibody, testing offers a dependable and convenient alternative to reverse transcription-polymerase chain reaction (RT-PCR) tests for dental clinics.

Suaris is a consultant anaesthetist in private practice with an interest in head and neck cancer and ENT. She also has an NHS contract and is no stranger to dentistry, owing to the fact that she provides sedation for dental implant surgery in her husband’s dental practice. Suaris spoke to Dental Tribune International (DTI) about the need for testing in dental settings, and the rapid antibody testing kit that Salubritas is offering to dentists.

“In dentistry, testing is very much voluntary at the moment, and we need to talk more about antibody testing,” she began. “It seems daft not to be using some sort of testing in dentistry, because we do tests in all other areas of medicine and surgery, and so why are we not applying some of the technology that we have got to risk stratify our patients in some way?”

“[The] actual fact is that the antigen test, which is the swab test that we do in hospitals, is only 50–70% accurate”
– Dr Priya Suaris, medical director, Salubritas

She says that the UK government and media have given antibody testing a bad name. “They have made everybody really wary of it, but the actual fact is that the antigen test, which is the swab test that we do in hospitals, is only 50–70% accurate. And so if you have got a very mild form of COVID-19 and you have a swab test, it might not pick it up and may give you a negative result. This is currently the ‘gold standard’ in the UK, but it is not really a gold standard at all. The reality is that we actually have got really good testing if you can get the right test and work around its limitations. I think that these [antibody tests] are really easy to use point-of-care tests in the dental practice.”

While PCR tests provide a direct look at what is going on in the patient on the day of the test, antibody tests are a different way of looking at things: essentially, they offer a look into the past, and can see if patients who have had symptoms have had the virus, but they can also identify those who have had it and been asymptomatic, and those who have had a recent infection.

Suaris says that, ideally, dentists should be using both. “The problem with PCR tests is that they take a couple of days so, unless you are going to be really strict with your patients and say, ‘Right, we are doing this test now, and you should self-isolate for two days until we get your test results back and you are back in our chair’, it is going to be really difficult when people start getting back to work. You can’t get dental patients to do that, no way.”

The rapid antibody testing kit being distributed by Salubritas costs around £15 (€16.75). (Image: Salubritas)

The testing kit on offer from Salubritas is a proven test that has been marketed internationally. It costs around £15 (€16.75) and can easily be administered by dental teams. It works with whole blood, blood serum and blood plasma, has a detection time of 10 minutes and tests for the two antibodies IgM and IgG simultaneously. Crucially, it is reported to be more than 98% accurate.

DTI asked Suaris about demand for the kits in the UK and the benefits of dental practices having a record of their patients’ history of COVID-19. “What has happened is that dentists have had so much to contend with, and no one has actually talked about antibody testing, so it has not really crossed their minds. But what is happening now is that they are going back to work and are starting to see the benefits of testing their staff. Soon, I think, they are going to start seeing the benefits of testing patients.”

“We are charging our patient for the test, but we are also having to charge our patients for the PPE. But once they have had the test, if they are positive, then they may not need to have another one again—at least, not in this current phase of COVID-19. But if they test negative, then we would continue to test them at regular intervals just to see whether things have changed,” she explained.

The rapid antibody testing kit also communicates with a smartphone app, and users can opt to share selected information digitally with their healthcare providers. More information on the test can be found here.

Tags: