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MRIGlobal’s Science Diction podcast dives in with research scientists to offer insight into point of need—how the pandemic helped improve access to diagnostics and the chemistry that provides you an accurate diagnosis.
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Dr. Amy Manning-Boğ
Have you ever swabbed inside your nose and used that sample to help diagnose if you have the flu or COVID 19? Or maybe you peed on a pregnancy test. The technology that makes those and other diagnostic tests like them possible is rooted in chemistry. Dr. Karen Peltier is an MIT and Princeton trained chemist responsible for managing disease diagnostic programs, shepherding them through initial design and development through FDA approvals.
Today on the show – Point of Need – how the pandemic helped improve access to diagnostics and the chemistry that provides you an accurate diagnosis. I’m Amy Manning- Boğ and this is Science Diction from MRIGlobal.
Karen Peltier, Ph.D.
So point of need diagnostics have been around for a while. For example, home pregnancy tests have been on the market since the 1970s. Tests for sexually transmitted diseases like HIV have been around since the 1990s. Now we have at home fertility tests and even DNA testing. The ability of people to manage health from the privacy of their own homes was further accelerated by the pandemic. We all remember working and schooling from home, getting groceries and other necessities delivered, as many of us were riding out quarantine for weeks and months on end, avoiding any public gathering. Instead of going to the doctor’s office and risk getting sick or infecting someone else, people raised their expectations for when and where they could diagnose their illness. At home testing took off and we never looked back.
Dr. Amy Manning-Boğ
Now I’ve heard of “point of care,” but you said “point of need.” Can you please explain the difference?
Karen Peltier, Ph.D.
Sure. Point of care refers to testing that is done at a doctor’s office or a clinic. Point of need refers to testing that can be done without the supervision of the care professional, usually at home. But it can also be done at airports to screen passengers getting on the plane or in schools. Essentially, everywhere there’s a need for testing results in real time performed by either the patient themselves or another lay user.
Dr. Amy Manning-Boğ
So was consumer demand prompted by the development of new technologies, or did that just open up the market for technologies that were already available?
Karen Peltier, Ph.D.
As so often happens in science, advances in technology and market demand play off each other. As people became more comfortable with the idea of at home testing, markets grew. At the same time, researchers expanded the types of testing that could be offered.
Most point of need tests currently on the market are based on lateral flow technology. This technology was first developed for pregnancy tests, but the basic chemistry behind how they work is relatively straightforward and can be applied to a wide range of targets – hormones, viruses, drugs of abuse, etc.
Dr. Amy Manning-Boğ
Now, it sounds like these are used in doctor’s offices?
Karen Peltier, Ph.D.
So, yeah, lateral flow tests have been used in doctor’s offices worldwide for a long time for HIV, malaria, strep and flu since the early 2010s. I remember going into the doctor’s office for my daughter to get a essentially a 15-minute strep test – that was going to be one of these lateral flow assays.
COVID has changed the way we think about these tests. As a consumer, I now want to know whether or not the fever, runny nose or headache I have is associated with COVID, flu, or none of the above. So I know whether or not I should go to the doctor’s office to seek treatment, self-isolate, or just drink lots of fluids and get rest, all without leaving my own home.
Dr. Amy Manning-Boğ
So, Karen, can you please tell me how a lateral flow assay works and how that provides an accurate diagnosis?
Karen Peltier, Ph.D.
So it’s a pretty elegant solution to a complex problem. Lateral flow tests can be designed to target different analytes, such as antigens. In the case of SARS-CoV-2, nuclear proteins are specifically targeted or antibodies or even specific molecules such as HCG, which is a hormone that a pregnancy test is based on.
Lateral flow tests are essentially a lab on a strip of paper. The sample is applied at one end, it can either be urine in the case of a pregnancy test or extracted from a swab, as in the case of most COVID tests. Once the sample is extracted, it is placed on the test strip and the paper acts like a sponge which draws the sample across the paper.
Dr. Amy Manning-Boğ
So when the liquid is going across the paper, what’s happening chemically?
Karen Peltier, Ph.D.
So at different points along the test strip, there are different chemistries. So at the front end, it’s where you’ll have essentially the reagents or the chemicals where the reaction is stored. As the sample drags across that surface, it’ll bind to a tag particle. It’ll keep moving further along the test strip, there’s a test line where another chemical partner has been immobilized in a line. As the target particles pass by, only the target will be trapped and your eye will see this colored line can be red, it can be blue. It really depends on the nature of the tagging of the particle. Unbound particles continue on further, essentially to the control line. There, the materials are trapped so that the fluid has made its way all the way across the test strip and the reagents were properly released. If the control doesn’t show up, then the user knows not to trust the test.
Dr. Amy Manning-Boğ
What other benefits do you see?
Karen Peltier, Ph.D.
Point of need diagnostics took a significant burden off of the health care system itself. Remember when we would line up in cars to get our noses swabbed? Oh, yeah, Yeah. The sample would then be sent off to a central lab for analysis, and it would be multiple days before we would get an answer. This took a lot of coordination and used up a lot of bandwidth.
Hospitals and doctors’ offices were spending most of their time on testing and not necessarily on treating patients. If people can test at home and only go to the doctor when they need to seek treatment, doctors and hospitals have more time to treat those that are truly sick.
Dr. Amy Manning-Boğ
So when a manufacturer comes to MRIGlobal with a new diagnostic, what’s the process for getting that approved for consumer use?
Karen Peltier, Ph.D.
Sure. The FDA has essentially guidelines that all device manufacturers have to follow. This is standardized testing. Testing includes items such as the:
We’re all familiar with COVID and the new variants that we have every few months. It’s important that our diagnostic tests can pick up all of those variants, the old ones as well as the new ones. So we do specific testing for that.
One of my favorite types of testing is what we call flex studies and these are the ways in which someone might misuse a test. For example, if the instructions say to drop three drops when you’re performing the test and you accidentally drop four, is the test still valid? What if you don’t place it on a flat surface while still developing or even drop it mid test? We check all of those things to make sure that the test is robust and will continue to work.
Dr. Amy Manning-Boğ
So you’re the ones responsible for making that package insert, aren’t you?
Karen Peltier, Ph.D.
That’s right. So if you look at the package insert, you’ll see all of the data essentially summarized that we’ve collected. It’ll have the limit of detection. It’ll tell you what organisms have been tested for cross-reactivity, and you’ll even notice the warning labels of saying don’t drop it or various things that failed flex testing.
Dr. Amy Manning-Boğ
So I imagine that clinical testing is also required?
Karen Peltier, Ph.D.
So what we’ve talked about so far is testing that’s done in the lab. And what we really need are real world samples as well. So what the companies will do is they go out, take their tests into the field and have real patients test using their device. And at the same time, a separate sample is taken and sent to a central lab like ours for a more in-depth testing to see whether or not that sample is truly negative or positive.
Dr. Amy Manning-Boğ
So are you looking for lack of inferiority or superiority?
Karen Peltier, Ph.D.
So, it really depends on the type of test we’re looking at. When we’re talking about these at home point of need tests, then it doesn’t have to be as good as a PCR test. We’re generally looking for something that at home, if you’re already feeling sick, are you sick? Is it COVID? So we’re looking to make sure there aren’t too many false negatives and false positives.
But really for a true in-depth diagnosis, you really should go for a PCR test in the lab, still This at home point of need testing is essentially a precursor to saying, “Yes, I have COVID and I’m going to the doctor.”
Dr. Amy Manning-Boğ
Though some point of need diagnostics have been around for decades, others are just emerging to address a range of disease states.
Karen Peltier, Ph.D.
Right now, a lot of companies are working on putting multiplex tests on the market. Those are tests that can essentially identify multiple diseases at once. They can detect COVID flu A, flu B, essentially anything that your child might come home from school with, RSV, can all put be put on a single test. And so I think that’s going to be what we’ll see next.
Dr. Amy Manning-Boğ
So this is fascinating. Where is this going, Karen?
Karen Peltier, Ph.D.
Even longer in the future, we’ll see the whole gamut of common infectious diseases that people will be able to test for at home. But it doesn’t just have to be infectious disease. There are all sorts of things that can be tracked – drugs of abuse, antimicrobial resistance, sexually transmitted diseases. Those are all areas where we currently have some testing, but I expect them to expand considerably going forward.
Dr. Amy Manning-Boğ
So where’s the real power in point of a need diagnostics?
Karen Peltier, Ph.D.
Point of need diagnostics are powerful for two reasons. One, they allow us to screen populations for illness quickly and easily and find out who needs to be treated and who can stay home. And it also helps us to get health care access into areas that are underserved. So areas where there may not be as many doctors available to meet with patients.
With the pandemic, we saw a lot more telemedicine. If you can do your test at home and then call into a doctor, that’s a new way of treatment. That’s not something we’ve done before. And this means that we can now get access to rural communities and other underserved populations.
Dr. Amy Manning-Boğ
And what’s the corollary of early detection?
Karen Peltier, Ph.D.
Early detection using point of need allows for early disease diagnosis, which leads to early treatment and importantly, containment, thus limiting the spread of disease.