COVID-19 TESTING 101
AN IMPORTANT MESSAGE FROM OUR CHIEF MEDICAL OFFICER GREGG DENICOLA MD
One of the most heated topics when reviewing patient feedback on our blog involves COVID-19 testing and the length of time to receive results as well as the availability of tests. We sympathize on the turn-around time complaints as we are as anxious to get these results back as our patients are. When the lab machine can handle 250 tests a day and they are getting 750, things back up as one may expect. Hopefully between lower demand and more machines we will see this be less of a problem soon.
So let’s do a “Testing 101” and emphasize three major issues:
1. Who should get tested?
2. What are the different type of tests now coming out?
3. When should a negative test be rechecked and a positive test as well?
Who Should Get Tested-
In the first blog post we went over the five major criteria- personal exposure, recent high risk travel, fever, upper and lower respiratory symptoms. What makes it confusing is that the CDC is leaving it up to each provider to determine the need for a test. One group may be very "tight" in their approvals, while others very "loose.” The wild card is the chronic lack of availability of the tests. Some days Caduceus starts the day with only 25 tests that would typically last a half day. Other days we wake up to 250 tests at our three swabbing centers.
Calling the local OC health department was of little help; they suggested a common sense solution. Save the tests for the highest risk patients- seniors, smokers, and those with impaired immune systems. So the days we are low, as CMO, I have had to tighten the approvals to those groups only. Other days, we are much more liberal in who we can screen.
Is this a form of rationing? Absolutely. It goes against everything we stand for as a medical group. Fortunately, we have never run out of tests since we started after they first became available. At this time we appear to have sufficient tests to keep our current testing capacity. We have done well over 500 tests, with a 6% positive rate. We commit to our patients- as long as we have it within our power –that we will have enough tests to continue testing daily as long as necessary.
We continue to insist that everyone who even THINKS they meet criteria, attempt to get tested. Otherwise, one may compare it to off-roading in a Jeep at night without headlights. Yes, one MAY be fine- until coming to a cliff.
Caduceus must give HUGE accolades to our Senior VP’s of Operations, Monique Wusstig and Katie Franklin. Their focus and determination to keep us fully stocked with swabs has been inspirational and life-saving.
The take home message?
If you have a fever or are sick, DO NOT IGNORE IT. Don't "watch" it. Ask your physician or provider a medical question at firstname.lastname@example.org. Schedule a video visit on our app or email our team at email@example.com. Get swabbed. We will figure out a way to get you tested.
Let’s discuss the different type of tests now coming to the market-
The gold standard--the only test Caduceus has used--is the "PCR" test on a nasal swab. This can detect as little as one virus particle in swabs taken from inside the nose. For Covid-19, the exact accuracy of PCR is unclear but PCR’s in general for other conditions are usually over 95% accurate.
The MOST important statistic is the "false negative.”
To be told you don’t have Covid-19 could be a disaster if you go back home and continue normal daily activities and sleeping habits with your spouse or partner and you really do have it.
A false positive is no picnic either; to stay quarantined alone and pray you do not contract life- threatening pneumonia when you don’t have Covid-19 at all is also not ideal.
The PCR nasal swab has very rare false positives or negatives.
The two problems with the PCR test are the lack of availability and the turnaround time on results, which should be three days, but has been over a week in some cases.
Enter the new antibody test. It’s a blood test and may be easier to find. Most only take 15 minutes, so you can get the result while you wait. Problem solved?
You guessed it; nope. The false negative rate is at least 10%. If we do 200 tests this week on that machine, 20 people will be told they are negative when they are actually positive. Also, there are different types of antibody tests with varying time for results and accuracy.
Some are even "fake" with reports that clinics charging are $250 for the test. My advice is NEVER to pay for a Covid-19 test. It’s against the law to charge the patient for the test. A doctor “on the level” will bill your insurance. As tempting as this test is, I’m afraid I MUST advise you to pass on the blood antibody test. One disclaimer- If we run out of PCR swabs for the long term, we WILL revisit using the antibody test.
A third player will enter the game in the next few weeks. Abbott Labs has a small machine intended for private medical and urgent cares. Called Abbott ID Now, it is a swab, not blood, and gives results in 5-10 minutes. They envision tens of thousands of these machines being utilized around the country through the month of April. Now we are “cooking with gas” right? Not so fast. Although Abbott hasn’t released exact data yet, one study shows a whopping 40% false negative rate!
Extreme caution must be used NOT to follow the temptation of a rapid test readily available. Time will tell if they are adequate for accuracy. If you’re skeptical of my cynicism, just Google “Theranos.”
The take home message?
I do NOT advise rapid "point of care" antibody blood tests or swabs on small machines at this time. The current PCR test is the gold standard for a reason. It’s accurate. The Covid-19 virus is not the time to be experimenting and risking a false negative or positive .Your life and the lives of your loved ones may depend on it.
Testing re-checks for both negative and positive-
Even though the PCR is accurate, are there times to re-swab? Yes. If you test negative, but you just landed from New York and then develop a fever, you need to be swabbed again. If you have a productive cough, test negative, but the cough worsens with trouble catching your breath, do a re-swab. If your partner tests positive, and you test negative, but you later spike a fever---you guessed it... re-swab. You could have another video visit to discuss things and confirm with the doctor but they WILL advise a re-swab.
What about those that have tested positive? When do they get swabbed again? Ahhh, this question is a bit trickier.
We call that a "test of cure" and it is very controversial. Mainly because it’s possible to stay positive for an extended period of time but we aren’t sure you're really contagious if symptoms have resolved. The CDC has gone on record as leaving it up to the treating physician or care provider whether to test a positive case until we receive a negative result. At first it was standard to re-swab once feeling better, but the trend now is swinging away from re- testing.
It is possible once the quarantine is over employers will require a “test of cure.” Bed partners may request one. Those seeking peace of mind will ask for one. At Caduceus we are taking this on a case by case basis. Surprisingly, most of our victims of Covid-19 have declined the “test of cure.” Most say they feel great and to save the swab for those that really need them. In times of crisis, we see that people really DO care.
The take home message?
If you test negative, don’t be bashful if your symptoms are new or persisting. We will re-swab you if there is any doubt. If you are recovering, you should discuss re-swab with your physician. We feel everyone who has any reason to be tested, should be.
After all, shouldn't we follow the lead of that great troubadour, Bob Dylan, who, in the song Rainy Day Women, sang "Everybody must get swabbed"?
Gregg DeNicola MD
Caduceus Medical Group
Chief Medical Officer