There’s no question that rapid antigen (Ag) testing is limited right now due to high demand: stores are sold out, health departments are prioritizing based on need, and online orders are delayed. While this shows that the U.S. government did not adequately prepare for Omicron, it also shows that people are finally leveraging one of the most under-utilized tools of the pandemic.
What would you suggest for those of us who are "hypersymptomatic" due to underlying conditions, such as allergies or acid reflux? One reason I use rapid tests is to justify fibbing about the stuff I always have. It's really the only way I have to rationalize going into work. Otherwise I'm forced to make impossibly subjective assessments of whether my cough is or isn't "dry" or "worsening" or if my nose is runnier than "usual". If someone comes up with a cough-o-meter I'll be more than happy to give up taking rapid tests.
Thank you for advising thriftiness! I see Curative is all booked up in our area. My wife is running into situations where patients are waiting over an hour in the waiting room to get tested.
I can’t help but imagine some people are getting/spreading Omicron simply due to the testing situation.
The difficulty is that there was never going to be enough testing capability to handle Omicron, and given the false negatives it may simply give people a false sense of security. Someone who is tested yesterday would need to be tested again today. It leaves the only solution being to test people with occupation need, for example aged care. Others should take steps to minimise exposure to themselves and especially to people at high risk. This is going to disappear quickly. When it ends it would be interesting to see what proportion of the population has had Omicron. Over 50% would not be surprising. Someone might avoid it this week but can they achieve that for the next month? One estimate for where I live is that at the peak we will have about 3-4% of the population as new cases per day. Be as vaccinated as you can, avoid crowds and hope it works out OK.
I always try to avoid talking about positive predictive values and negative predictive values, but this does play into our rapid tests. A positive result is pretty reliable (good specificity), a negative test is m'eh! (poor sensitivity). My issue, and an infection control guy is if you are symptomatic, and test negative (even with PCR) you still are symptomatic and could be spreading another respiratory virus to susceptible people. I am watching the numerous outbreaks around me in LTC of RSV and Rhinovirus...and I am always thinking, "I bet they tested negative for COVID and went to work!". Thanks so much for all you and your team does!
Excellent point. If you're symptomatic and test negative for SARS-CoV-2, the fact that you're symptomatic suggests you're likely still positive for something. STAY HOME! Don't become another vector!
Even in my days of healthcare IP, if I had a cold, I wore a mask if I had to go on the floors. When I was a lab tech, and taking blood, I would let the patient know that I had a mask on as I had a cold...even years ago the patient was fine with this concept of me protecting them. As you are probably aware, wearing a mask was socially acceptable in many countries prior to COVID if you were sick...just never caught on here in N America
I wore masks all the time... I spent a LOT of time in the OR and there were literally days I forgot to take the mask off before walking to the car. Same for isolation and reverse isolation. Lots of mask time. Even today, I've got a mask on when out in the real world. And it fits and is appropriate. I'm often the only customer in a store with one (except the AFB Commissary, where everyone has a mask, even if a bunch of them don't wear it right).
Thank you so much for this information. The question I have for you regarding the saliva swabs is: Are we able to use the Binax now at home tests to swab our throats and will it give us an accurate result as opposed to swabbing our nose? I was told at our testing site that it would need a different reagent to read the saliva? Is that correct? The only reason I ask is because this method is trending online. When a family member swabbed their nose it was negative, when they swabbed their throat, positive. They went and got a PCR test done and it was negative so why would they get a positive reading with the saliva swab?
Interesting, because I self-tested monday using flexflow after experiencing very mild cold symptoms over the weekend. Did a throat swab + nasal (as indicated in the article; I used the NIH video as a guide) and got a very very dark red line. I did not bother trying to get a PCR to confirm since I WFH. My testing is b/c I was supposed to have some medical appointments today, and didn't want to go in if I could spread. In the words of the dinosaur from Toy Story, "now I have doubt.."
By your description, you had a positive test result. Positive test results from antigen tests are considered, well, positive. tests that are flatly negative are "presumptive negative" and need a repeat to confirm, in 24-72 hours. tests that are not a hard, dark line, equivocal, should be considered positive.
There are things that can generate a false positive. If Melissa is correct that saliva and current reagent can give a false positive then I may not actually be positive, right?
I’m still acting as if I’m positive right now, but I’m also keenly interested in answering the question of whether I actually have it as that will affect decisions moving forward, as I assume that risk of reinfection to me is low.
That's exactly what I'm doing--for the purposes of stopping further spread. But if it's a false positive, then I'm at greater risk of future infection once I emerge from isolation.
Treating it as a positive now helps others; KNOWING whether it's really a positive helps future-Chris. I want to help both.
So: are you vaccinated? Boostes? If you're relying on prior infection for immunity, and you've now gotten omicron, and it's mild, you're pretty good. If not omicron, you're still at risk. If you're vaccinated and boosted, your risk for infection is lower but non-zero, but your presentation should be much milder.
For Shield saliva testing they say to wait an hour to test after having anything in the mouth, even an eraser (it’s on their site). If you waited an hour, I’d think positive. I didn’t watch the video yet. Also, I believe ppl with omicron can still get other variants & vice versa (tho if delta protection is longer).
Your article last evening included a reference to a study that pooled 70 other studies that showed the effectiveness of masks. Could you post a link to that particular study? Thanks.
I did a quick search through your blogs, but didn't quite see what i was looking for. Did you mention or do a write up on the antigen tests and the flu. I overheard a friend say that the tests pick up on flu more so than covid, and I for the life of me can't find really anything to support that or negate that. Care to give some insight or direct me to some reading to explain that?
I am very confused and need guidance. I tested positive on PCR and home rapid Dec. 28. No-one I was in contact with the entire week before has tested positive. I had barely any symptoms for three days, never a fever. I have not had a symptom for ten days now, I feel great, but I am on Day 14 and I still test positive on rapid home test (tested positive on PCR on Day 10). Am I contagious? Can I see people? Should I keep testing? Help!
I hope that the question most people are asking is do I need to isolate?. The problem is if they want to see their grandmother who has COPD and they think that she will be OK if they pass the test. Real world test performance seems to be very important. The Cochrane review last year had the sensitivity for asymptomatic patients at an average 58%. That indicates they are more suitable for someone working in a nursing home where every outbreak is a large problem, so a 50% reduction is important.
So honored to be a paid subscriber! Is there a source for not testing until 60 days after a positive case? I know SHIELD Illinois says 90 days, but their test is Gold Standard. CDC says 90 also w/PCR but also says if no symptoms, w/o clarifying. Thank you!
Thank you so much for this clear explanation and for the helpful links. I especially appreciate your clear guidance about what we as individuals should do.
Can you or anybody translate this cdc bulletin? Our local school board has translated it as pcr tests are no longer a valid dx tool. I can’t imagine that is true?
PCR tests are still valid! The CDC was recommending upgrading to an comprehensive PCR test suite for improved efficiency. That is all. These alerts are meant for labs, not for consumers like us, so it is easy to be confused by them.
Q: Why is CDC retiring the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel?
A: CDC is retiring the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel because the U.S. Food and Drug Administration (FDA) has authorized hundreds of other SARS-CoV-2 diagnostic tests, many of which are now higher throughput or can test for more than one illness at a time.
Q: Does the retirement of this test apply to all RT-PCR-based tests or all SARS-CoV-2 tests that have received Emergency Use Authorization from FDA?
A: No. The discontinuation of Emergency Use Authorization (EUA) only applies to the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel test. It does not affect any other SARS-CoV-2 test that has received EUA from FDA.
Q: Is CDC retiring the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel because it has produced inaccurate results?
A: No. There are no performance concerns with this test. The CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel is a highly accurate test. It has been used to successfully detect SARS-CoV-2 since February 2020.
Your third subhead should be "real worLd performance." Your Local Editor (Also, thanks for this--it is extremely useful and actionable information.
What would you suggest for those of us who are "hypersymptomatic" due to underlying conditions, such as allergies or acid reflux? One reason I use rapid tests is to justify fibbing about the stuff I always have. It's really the only way I have to rationalize going into work. Otherwise I'm forced to make impossibly subjective assessments of whether my cough is or isn't "dry" or "worsening" or if my nose is runnier than "usual". If someone comes up with a cough-o-meter I'll be more than happy to give up taking rapid tests.
Thank you for advising thriftiness! I see Curative is all booked up in our area. My wife is running into situations where patients are waiting over an hour in the waiting room to get tested.
I can’t help but imagine some people are getting/spreading Omicron simply due to the testing situation.
The difficulty is that there was never going to be enough testing capability to handle Omicron, and given the false negatives it may simply give people a false sense of security. Someone who is tested yesterday would need to be tested again today. It leaves the only solution being to test people with occupation need, for example aged care. Others should take steps to minimise exposure to themselves and especially to people at high risk. This is going to disappear quickly. When it ends it would be interesting to see what proportion of the population has had Omicron. Over 50% would not be surprising. Someone might avoid it this week but can they achieve that for the next month? One estimate for where I live is that at the peak we will have about 3-4% of the population as new cases per day. Be as vaccinated as you can, avoid crowds and hope it works out OK.
For sure they are!
I always try to avoid talking about positive predictive values and negative predictive values, but this does play into our rapid tests. A positive result is pretty reliable (good specificity), a negative test is m'eh! (poor sensitivity). My issue, and an infection control guy is if you are symptomatic, and test negative (even with PCR) you still are symptomatic and could be spreading another respiratory virus to susceptible people. I am watching the numerous outbreaks around me in LTC of RSV and Rhinovirus...and I am always thinking, "I bet they tested negative for COVID and went to work!". Thanks so much for all you and your team does!
Excellent point. If you're symptomatic and test negative for SARS-CoV-2, the fact that you're symptomatic suggests you're likely still positive for something. STAY HOME! Don't become another vector!
Even in my days of healthcare IP, if I had a cold, I wore a mask if I had to go on the floors. When I was a lab tech, and taking blood, I would let the patient know that I had a mask on as I had a cold...even years ago the patient was fine with this concept of me protecting them. As you are probably aware, wearing a mask was socially acceptable in many countries prior to COVID if you were sick...just never caught on here in N America
I wore masks all the time... I spent a LOT of time in the OR and there were literally days I forgot to take the mask off before walking to the car. Same for isolation and reverse isolation. Lots of mask time. Even today, I've got a mask on when out in the real world. And it fits and is appropriate. I'm often the only customer in a store with one (except the AFB Commissary, where everyone has a mask, even if a bunch of them don't wear it right).
Thank you so much for this information. The question I have for you regarding the saliva swabs is: Are we able to use the Binax now at home tests to swab our throats and will it give us an accurate result as opposed to swabbing our nose? I was told at our testing site that it would need a different reagent to read the saliva? Is that correct? The only reason I ask is because this method is trending online. When a family member swabbed their nose it was negative, when they swabbed their throat, positive. They went and got a PCR test done and it was negative so why would they get a positive reading with the saliva swab?
No place I've read recommends a different reagent for saliva, but I'll check.
Interesting, because I self-tested monday using flexflow after experiencing very mild cold symptoms over the weekend. Did a throat swab + nasal (as indicated in the article; I used the NIH video as a guide) and got a very very dark red line. I did not bother trying to get a PCR to confirm since I WFH. My testing is b/c I was supposed to have some medical appointments today, and didn't want to go in if I could spread. In the words of the dinosaur from Toy Story, "now I have doubt.."
By your description, you had a positive test result. Positive test results from antigen tests are considered, well, positive. tests that are flatly negative are "presumptive negative" and need a repeat to confirm, in 24-72 hours. tests that are not a hard, dark line, equivocal, should be considered positive.
There are things that can generate a false positive. If Melissa is correct that saliva and current reagent can give a false positive then I may not actually be positive, right?
I’m still acting as if I’m positive right now, but I’m also keenly interested in answering the question of whether I actually have it as that will affect decisions moving forward, as I assume that risk of reinfection to me is low.
I would treat it as a positive test at least for now.
That's exactly what I'm doing--for the purposes of stopping further spread. But if it's a false positive, then I'm at greater risk of future infection once I emerge from isolation.
Treating it as a positive now helps others; KNOWING whether it's really a positive helps future-Chris. I want to help both.
So: are you vaccinated? Boostes? If you're relying on prior infection for immunity, and you've now gotten omicron, and it's mild, you're pretty good. If not omicron, you're still at risk. If you're vaccinated and boosted, your risk for infection is lower but non-zero, but your presentation should be much milder.
For Shield saliva testing they say to wait an hour to test after having anything in the mouth, even an eraser (it’s on their site). If you waited an hour, I’d think positive. I didn’t watch the video yet. Also, I believe ppl with omicron can still get other variants & vice versa (tho if delta protection is longer).
I had to become a paid subscriber after reading such clear and helpful information.
What about this study ??
Study about inaccuracies in rapid tests:
https://www.statnews.com/2022/01/05/study-raises-doubts-about-rapid-covid-tests-reliability-in-early-days-after-infection/
Your article last evening included a reference to a study that pooled 70 other studies that showed the effectiveness of masks. Could you post a link to that particular study? Thanks.
Hi Dr. Jetelina,
I did a quick search through your blogs, but didn't quite see what i was looking for. Did you mention or do a write up on the antigen tests and the flu. I overheard a friend say that the tests pick up on flu more so than covid, and I for the life of me can't find really anything to support that or negate that. Care to give some insight or direct me to some reading to explain that?
Thank you for all that you're doing <3
Dr. Jetelina: I am in the same situation as SS below. But I have a different question. What is the antigen test picking up that the test is positive?
Thanks for all good science and translation.
I am very confused and need guidance. I tested positive on PCR and home rapid Dec. 28. No-one I was in contact with the entire week before has tested positive. I had barely any symptoms for three days, never a fever. I have not had a symptom for ten days now, I feel great, but I am on Day 14 and I still test positive on rapid home test (tested positive on PCR on Day 10). Am I contagious? Can I see people? Should I keep testing? Help!
Hi, what are your thoughts on the recent FDA tweets about not swabbing the throat as well as nostrils?
I hope that the question most people are asking is do I need to isolate?. The problem is if they want to see their grandmother who has COPD and they think that she will be OK if they pass the test. Real world test performance seems to be very important. The Cochrane review last year had the sensitivity for asymptomatic patients at an average 58%. That indicates they are more suitable for someone working in a nursing home where every outbreak is a large problem, so a 50% reduction is important.
So honored to be a paid subscriber! Is there a source for not testing until 60 days after a positive case? I know SHIELD Illinois says 90 days, but their test is Gold Standard. CDC says 90 also w/PCR but also says if no symptoms, w/o clarifying. Thank you!
Thank you so much for this clear explanation and for the helpful links. I especially appreciate your clear guidance about what we as individuals should do.
Good morning Dr Jetelina!
Can you or anybody translate this cdc bulletin? Our local school board has translated it as pcr tests are no longer a valid dx tool. I can’t imagine that is true?
https://www.cdc.gov/csels/dls/locs/2021/07-21-2021-lab-alert-Changes_CDC_RT-PCR_SARS-CoV-2_Testing_1.html
Thank you
PCR tests are still valid! The CDC was recommending upgrading to an comprehensive PCR test suite for improved efficiency. That is all. These alerts are meant for labs, not for consumers like us, so it is easy to be confused by them.
The CDC's follow-up alert clarifies all of this:
https://www.cdc.gov/csels/dls/locs/2021/08-02-2021-lab-alert-Clarifications_about_Retirement_CDC_2019_Novel_Coronavirus_1.html
-----
Q: Why is CDC retiring the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel?
A: CDC is retiring the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel because the U.S. Food and Drug Administration (FDA) has authorized hundreds of other SARS-CoV-2 diagnostic tests, many of which are now higher throughput or can test for more than one illness at a time.
Q: Does the retirement of this test apply to all RT-PCR-based tests or all SARS-CoV-2 tests that have received Emergency Use Authorization from FDA?
A: No. The discontinuation of Emergency Use Authorization (EUA) only applies to the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel test. It does not affect any other SARS-CoV-2 test that has received EUA from FDA.
Q: Is CDC retiring the CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel because it has produced inaccurate results?
A: No. There are no performance concerns with this test. The CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel is a highly accurate test. It has been used to successfully detect SARS-CoV-2 since February 2020.