How Coronavirus Test Kits Work | WSJ

How Coronavirus Test Kits Work | WSJ

(gentle music) – [Narrator] Researchers around the world are hustling to create this test kit. The rapidly-spreading new
coronavirus has put test kits at the center of how infected
patients are diagnosed, so they can get treatment quickly. But there’s one issue with these nose and throat-swabbing tests. The results aren’t always accurate. At the center of the epidemic in Wuhan, some people tested negative, only later to find out that
they actually have the disease. In the U.S., the CDC sent out test kits to public health labs
that gave inconclusive results in the verification process. The unreliability of
these tests even forced Chinese health officials to expand how they classify patients,
which resulted in a surge of more than 14,000 cases in one day. They are now including
results from test kits and other diagnostic
methods like chest scans. So how do these test kits exactly work, and why are there so many problems? This government lab in
Singapore has produced test kits for the
country’s public hospitals. It’s also shipped about
10,000 tests to China. Dr. Sidney Yee leads the
team that developed them. She says most doctors
use a type of lab test called RT PCR, which can
be used to detect small amounts of pathogens
including viruses like HIV. – So this is the gold
standard that’s being used. What it does is, it
actually directly detects the presence of the pathogen. – [Narrator] It’s pretty easy to use. A doctor collects samples from a patient by swabbing the nose or throat for mucus. Those swabs are then
sent to a lab for a test that detects the genetic
material of a pathogen. The sample is first mixed
with reagents in a tube, then put into a machine that duplicates the genetic material.
(machine whirring) So if the virus exists, these copies will amplify its presence, confirming that a patient has tested positive for the coronavirus. Dr. Yee says the first place for error could be at the swabbing stage. – Most of the time, the
sampling for COVID-19 comes from a throat swab. COVID-19 is actually a
lung infection disease, so doing the throat swab
really depends on how much of the pathogen you’re able to capture. – [Narrator] Another place
for error is the time it takes for the sample to reach the lab. – [Sidney] The pathogen on
the swab is not going to last for many, many hours,
so that transportation, the logistics, is also important. – [Narrator] Transportation
is a huge hurdle in Wuhan, where the city has been on
lockdown since mid-January. – [Sidney] When the
sample gets to the lab, what is the infrastructure of the lab that is able to deal with running tests, as well as the expertise
and the experience of the lab technicians that
are running these tests? – [Narrator] Dr. Yee says
the most critical moment for human error is when doctors
decide to use the test kit. For instance, many people have
been showing mild symptoms, but that doesn’t mean they
don’t have the pathogen. – It’s very hard to make
the direct correlation between what our test kit can be used, on which stage of the disease progression, with respect to how much the pathogen is present in the patients. – [Narrator] Just how
accurately these test kits are being used is on trial in Wuhan. Here, hospitals have been overstretched with limited resources. There are not enough
staff to swab patients, and labs are inundated with the backlog of samples that wait to be tested. – [Sidney] There are many,
many different steps, and different processes
involved in just running a test. It’s not just with respect
to the test kit itself. (gentle music)

35 thoughts on “How Coronavirus Test Kits Work | WSJ

  1. In Hawaii, they're sending swabs to the CDC on the mainland, and they say it takes weeks to get the results. Gee, I wonder if that's too long to be accurate?

  2. Use artificial intelligence on CT scans of lungs in addition to RT PCR:

  3. So, this Singapore test kit is useless. Btw, 10k shipped to Wuhan, is a drop to the ocean. CCTV said, test kit are manufactured in Shanghai one Trade Pilot Zone.

  4. This explains why there's so much inaccuracy in the case numbers around the world. Thank you WSJ for posting this very informative video.

  5. Send this to Japan ASAP. Japanese government is so scared of their Olympics being canceled, hospitals in Japan are forcing people who are sick just to go home and die. They are refusing to test infected people. Japanese government is known for ignoring problems until they go away no matter what human costs are, that's exactly what they are doing. True scumbags. If I were you I would NOT be going to Japan for the Olympics game. Japan is way worse than China right now as they don't do anything to quarantine. Unofficial statistics for Japan is way worse than other countries at the moment.

  6. The video presents a false argument. The video barely goes in depth on how the test works in the first place and then starts to lay out points that are not even inherent to the test to imply that the test is inherently flawed.

    I can agree that the time it takes to transport sample swabs is important, but the video doesn’t even mention how long it actually takes for for the lab to receive them. We shouldn’t rely on hearsay in the comments.

    The test kit detects if the patient has the viral polymerase (a vital protein that is highly conserved in the virus). If the virus doesn’t have this polymerase then it is unable to replicate within the patient’s cells, so it’s a good marker to look for in detecting the virus.

    There is nothing wrong in the kit itself. Most of the things mentioned in this video are factors that don’t pertain to the kit like number of staff, time of testing, and time for transportation. 

    What she said ~3:00 is admirable. The pathogenesis stage of the virus matters for the test. The test may come out negative if the virus hasn’t replicated within the cell or hasn’t attached, so the test will come out “false negative.” This doesn’t mean that the test is inherited flawed. Like I said before it’s the timing of the test that matters.


  7. Officials at the U.S. Centers for Disease Control and Prevention admit that a significant proportion of the 10 thousand 3 thousand people who died of influenza in 2019 were caused by the new coronavirus.
    It bothers me

  8. How about this, I blow my nose on a clean untouched paper, and they look at it under the high powered microscope, and see if they see the little virus swimming in my mucus. real time test. since it can live on surfaces for days, it should be there.

  9. Two months after China issued the first warning, the entire US can do 16 tests per day. What a good job CDC is doing preparing for the inevitable pandemic.

  10. Hospitals are billing $3,500 for each Coronavirus test…. adding to the already 900,000+ medical bankruptcies/yr. US Healthcare is a JOKE!!!

  11. reverse genetics is the issue. Wuhan coronavirus is highly suspicious. authors who did revierse genetics on coronavirus 5 years ago, in a journal, should explain it. too similar

  12. What if patients mucus from coughing was collected for sampling. If COVID-19 is a lung virus. Would the materials collected from a patients cough be more likely to test correctly?

  13. You can be infested with one tiny virus, while it's not yet duplicated, so not only this test is flawed in many levels, it's useless as a detection device. This flu like virus is not stoppable unless a full mandatory quarantine is imposed on everyone on earth for a period of 1 month, waiting it to die out by itself, or an efficient vaccine is creating on time to fight it. Both case is very unlikely to happen, thus my conclusion, you are fked. You will have a 65% chance of dying if you are over 50 years within next few months. Good luck, Old fkers!!

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