I tested negative. Am I safe?

More folks than ever are getting tested for SARS-CoV-2, the virus that causes COVID-19. Access to testing is great, and long overdue.

But the tests themselves remain problematically inaccurate, so remember that a negative test doesn’t necessarily put you in the clear.

The issue is false negatives: tests that don’t detect the virus when a person is actually infected. And these tests we’re using to determine viral presence is prone to false negatives.

This matters because people who test negative may take fewer precautions to protect those around them — even though they may actually be infectious.

If you’re sick, pay attention to your experience rather than your test results — and act accordingly. But if you’re not sick, don’t take the test’s word for it.

How bad is the problem? Researchers at Johns Hopkins School of Public Health scoured the existing scientific literature — both published, peer-reviewed studies and those that are still going through the process — to answer that question. They looked at data for the RT-PCR test, generally a very sensitive way to detect viruses, that is the primary swab-up-the-nose test used to detect active infection.

The short version: At best, one in five tests will have false negatives.

Published in the May 13, 2020 edition of Annals of Internal Medicine, the study found a sweet spot in the progression of infection. Testing on Day 8 of the infection — usually the third day of disease symptoms — is when you’re most likely to get the most reliable results.

Here’s how it breaks down:

  • Day 1 of infection (often no symptoms): 100-percent chance of a false-negative test.
  • Day 4 of infection (often no symptoms): 67-percent chance of a false-negative test.
  • Day 5 of infection/symptom onset: 38-percent chance of a false-negative test.
  • Day 8 (three days after symptom onset): 20-percent chance of a false-negative test.
  • Day 9 (4 days after symptom onset): 21-percent chance of a false-negative test.
  • Day 21: 66-percent chance of false-negative test.

These numbers represent median observations: in half the cases the chances were higher, in half they were lower. This is the middle ground of numbers that have a pretty large spread, especially when testing the early days of infection.

Going with these median numbers, you’ll see that even at the Day 8 sweet spot, one in five tests will falsely report a negative result when the person is actually positive. So at best there’s a 20% false negative rate. On other days, the false negative rate is even higher.

Why are the false negatives so high on a test that is known to be exquisitely sensitive? A physician colleague of mine working in a front-line lab suggests that incorrect or incomplete collection may be the problem. The swabs healthcare workers stick up patients’ noses may just not be catching enough viral particles. I’ve got a message out to a microbiologist friend for his take, and will update this post when I hear back.

I get that people want to know what’s going on. I want to know what’s going on. These acute tests (the swab-up-the-nose tests) more usefully inform our actions when they’re positive than when they’re negative.

If you get a positive test, talk to your doctor about appropriate medical care, stay home, stay away from people, and do everything you can to take care of yourself.

If you get a negative test, don’t assume you aren’t sick or that you can’t infect others. If you aren’t on your third day of symptoms (and even if you are), there’s a good chance the test won’t catch your infection.

Be careful, folks. And remember that getting a negative test isn’t the final word.

Salúd!

—Dr. Orna

P.S. Read the full Annals of Internal Medicine article, “Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction–Based SARS-CoV-2 Tests by Time Since Exposure.” Here are the key findings if you don’t want to wade through it:

“Over the 4 days of infection before the typical time of symptom onset (day 5), the probability of a false-negative result in an infected person decreases from 100% (95% CI, 100% to 100%) on day 1 to 67% (CI, 27% to 94%) on day 4. On the day of symptom onset, the median false-negative rate was 38% (CI, 18% to 65%). This decreased to 20% (CI, 12% to 30%) on day 8 (3 days after symptom onset) then began to increase again, from 21% (CI, 13% to 31%) on day 9 to 66% (CI, 54% to 77%) on day 21.”

Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction–Based SARS-CoV-2 Tests by Time Since Exposure.Annals of Internal Medicine, 13 May 2020.

Photo by Hans Reniers on Unsplash

eat your flowers! here are my 5 favorites

My med-school bestie is starting her first(ish) garden this year. She’s mostly growing veggies in pots, mostly on the porch of her Seattle apartment. She’s found gardening to be a positive thing in her current pandemic reality, soothing and exciting and rewarding.

We’ve been talking about plants a lot, and as you might expect, I am overwhelming her with ideas.

During our call last night, we talked about flower power: specifically, which are edible and delicious and easy to grow. I promised her a short list, which I’m sharing now with you.

1. Roses:

My front-yard roses always look ragged because I take a nibble whenever I walk past. Some varieties are tastier than others, but the best can taste much like they smell. Rose petals give a great mood boost, with a fair bit of astringency to tighten and tone tissues. Just make sure you eat only unsprayed roses; those you’ve grown yourself are best. Preserve your harvest with rose petal honey, one of my favorite rites of spring. (Catch the video here.) 

2. Daylilies :

These are super hardy perennial plants with prolific, if short-lived blooms. They don’t have a ton of flavor in my experience, but they’re great for a solid, floral texture. You can eat these raw, but they hold up to cooking. Pick flowers or buds and add to soups for a spot of color and joy. If you plant them, they will spread — so you can share bulbs with your neighbors and lift up your neighborhood. (Pictured above.)

3. Calendula:

It’s hard to imagine any herbalist would leave Calendula off a top-plants list. This sunny plant is incredibly easy to grow, self seeds prolifically (but is easy to remove if, for some reason, you want to), shines in the garden for much of the year and offers great medicine for acute and chronic conditions. Its mild flavor makes for easy garnish on salads, or a sunny wintertime tea. Medicinally it’s used to heal wounds externally and internally, and helps keep the lymphatic system moving as it’s supposed to. (That’s important for immunity!) 

4. Lavender:

If you’ve been watching my (mostly) daily plant walks on Facebook and Instagram live, you know that lavender is my plant of the year for 2020. Look for an in-depth post about why coming soon. The short version: Lavender leaves and flowers are mood elevating, calm inducing, digestion enhancing and overall microbe busting. A perfect plant for these times. 

5. Nasturtiums:

Unlike many edible flowers with unremarkable flavors, Nasturtiums carry considerable kick. All part of the plant are significantly peppery. Add flowers to spice up salads or garnish other dishes. Toss in some leaves where you’d otherwise add mustard greens — a close cousin. Pickle the green seeds (shaped like little brains) for a homemade alternative to capers. The flowers and leaves are high in Vitamin C and offer antimicrobial benefits as well.

 Honorable mention: Violets were my 2019 plant of the year, and they deserve a spot on these kinds of lists. The only reason I’m leaving them off the list is that they’re mostly done flowering for the year. Note that there are many kinds of Viola going by different names: pansies and Johnny Jump Ups are different species of the same plant.
 
If you’re able to get outside this weekend (or better still, get into a garden), I hope you’ll look at the flowers around you with slightly different eyes. Remember, it’s not cool to take other folks’ plants without permission. But if you’ve got a pot or a plot with some flowers in it, consider whether they’d make an edible addition to your weekend meal plans.
 
This is just a quick list, and is by no means an exhaustive one. Did I miss your favorites? Shoot me an email and let me know.
 
Salúd!
 
—Dr. Orna
 
P.S. I’m still doing my online plant walks most weekdays. I generally go out on Facebook at 3pm PDT and jump over to Instagram at 3:30pm. This changes sometimes based on my patient schedule, and I note the times on both platforms each morning. The walks are recorded if you can’t make it live, but it’s more fun if you join!
 
P.P.S. If you’d like to talk about how plants and I can help you with your personal health questions, just drop me a line. If you’re in Oregon, click here to book your appointment.

no one is free until we all are free.

In the midst of a pandemic, the most recent series of assaults and deaths of black Americans at the hands of white ones has erupted in protest of systemic racial oppression.

As a naturopathic doctor, one of my core principles is to treat the underlying cause of disease. Sometimes the cause is not eating vegetables. Sometimes the cause is 400 years of systemic oppression.

Right now, the COVID19 pandemic is disproportionately sickening and killing African Americans. I’ve written about this in my Saturday C0V1D Reading Roundups. (All people of color are getting hit hard, but this week I want to keep the focus on African Americans.)

Why is this happening?

  • Disparities in access to medical and preventive health care.
  • Healthcare providers dismissive of black medical concerns. One example is Rana Zoe Mungin, a 30-year old teacher who died of COVID19 after being turned away for testing twice. (Here’s a discussion of the phenomenon from New Hampshire Public Radio.
  • Well-earned distrust of the medical system. (See this article from The New York Times.)
  • Physiological repercussions of historical trauma. (Check out this great Instagram post by my colleague Dr. Gaynel Nave.) This trauma is also current and ongoing.

And it’s not just COVID killing black people. It’s racist police, racist neighbors, a racist medical system and a whole country built on the backs of people of color.

Some recent names, in case you hadn’t heard them: George Floyd in Minneapolis, MN. Breonna Taylor in Louisville, KY. Ahmaud Arbery in Glynn County, GA. Tony McDade in Tallahassee, FL. Dion Johnson in Phoenix, AZ.

As a doctor, I stand for treating root causes. That means I stand against racism in all its forms.

For those of us with the privilege of light skins, what can we do?

  • See and acknowledge the racism in society and in ourselves
  • Dig into the past and current history of anti-black oppression. 
  • Seek out and listen to black voices (as well as those of indigenous and other peoples of color.) 
  • Then amplify those voices. 
  • Speak and act in solidarity with anti-oppression movements. 
  • Support black individuals and businesses.

There is a lot to do, whether or not you take it to the streets.

You know I’m not someone to stay silent. But I’ve had a tough time this last week finding my words — because I got stuck looking for the right ones.

Here are two quotations from black women that I’ve been holding close to my heart.

First, from my childhood friend Renee White, quoted with permission:

“White folks need to dismantle white supremacist structures. We need to see that work done loudly, publicly, and embracing the professional and personal toll that will be required. I figure since the very existence of my people puts us at risk then that’s the least they can do. I’m done being gentle with my words. I know my white friends can handle it.”

Second, from creator Kandise Le Blanc, whom I don’t know personally:

“I want your activism to be questioned and challenged and criticized by Black people. I want you to grow from your mistakes so we can grow as a nation”.

(Read her whole piece here.)

Silence is complicity. So I am speaking up.

I will work against any system that continues to diminish, target and murder people based on the color of their skin. I am imperfect in my actions, and remain committed, as I have throughout life, to increasing freedom and equality in this world.  

If there was ever a time to be courageous, it is now. The world is at a tipping point. What we say now and do now will define life for generations. I hope you will join me in this work.

For freedom,

—Dr. Orna

P.S. There’s a tremendous amount of great stuff happening on Instagram this week, where many people are working to actively amplify the words of black people. Below are some of the folks I’m following and reposting, plus resources many folks have shared. I encourage you to check them out.

Some awesome people to follow on Instagram:

RESOURCES:

Antiracism resources.

Compliation of resources, donations.

Activist and support resources.