Coronavirus Testing Keeps Labs Working Day And Night
While the fight against the coronavirus is going on in clinics, hospitals and testing sites, it began in the clinical lab.
“In this case, they were able to grow the virus and do molecular testing on it. And that’s how we figured out it was a brand new virus” said Dr. Bobbi Pritt, a clinical microbiologist at the Mayo Clinic in Rochester, Minnesota and is part of Mayo’s COVID-19 response team. “And then the molecular virologists, the people who study virology and viruses, got together and realized it was very, very similar to the virus that caused SARS back in 2003.”
However the outbreak of SARS, or severe acute respiratory syndrome, was not as widespread as the current pandemic. According to the World Health Organization (WHO), a total of 8,098 people worldwide became sick with SARS during the 2003 outbreak. Of these, 774 died. The U.S. had only 29 confirmed cases and no deaths from SARS.
Today, testing for COVID-19 is an important way to try and keep the outbreak contained. Dr. Pritt says developing a test involves a lot of hard work in the lab.
“First, you need to have scientists take a good look at the virus, do some molecular testing, and be able to uncode, or decode its entire genetic material so that we know all the little pieces that make up its genes. And in this case it’s an RNA virus."
(Editor’s note: RNA is ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.)
"So we need to know all the pieces of that RNA, its whole genome. So scientists did that early on, and thankfully, in this day of readily sharing (information) across the internet, they posted this online. Everyone had access to it. That was great. Then it’s just a matter of looking at the different parts of the coronavirus, looking at its RNA, and knowing what we know about viruses already, figure out what would be a good region (of the virus) that we would want to detect in a test.”
In the lab, scientists take that piece of the virus’s genetic code and amplify it until there is so much it can be easily identified by a test called PCR, Polymerase Chain Reaction. Dr. Pritt says that’s the test most labs are working with today. However there may also be a way to detect antibodies against the coronavirus in a patient’s blood.
“It takes about eight days for those antibodies to get to a level that they are really detectable. (Then) we can do a second type of test called serology where we could actually detect the antibodies."
(Editor’s Note: Serology is the scientific study or diagnostic examination of blood serum, especially with regard to the response of the immune system to pathogens or introduced substances.)
"Then you could say ‘ok, this person was infected’. And at that point you’d know if they were better or not. Possibly at that point, if they no longer have symptoms, you could say they had the virus, they recovered, and you could start thinking about how to make decisions of sending them back to work.”
As you might expect the demand for tests has laboratories working around the clock, including Dr. Pritt’s lab at Mayo Clinic.
“We are running (our lab) now for three shifts. The laboratory that does this testing didn’t used to work day and night. They do now. So we crank out as many of these (test) as we can. We even have (opened) a separate laboratory (that) is also doing additional testing. Right now we (are testing) about 5,000 specimens in a 24-hour period. Our turnaround time, we say that we want to be around 24 hours. We are actually significantly less than that. It’s probably (closer to) about 10 hours or less. But other labs, I think, are struggling with longer turnaround times. Some of the large reference labs are more at a three, four, even five-day turnaround time.”
However there are now accelerated PCR tests coming into the market that have only a 15 to 45-minute turnaround time from swab to result.
“Those are great. Those (tests) are commercial products made by companies like Abbott. And those are available in very, very limited quantities. Those are tests that could even be done at a doctor’s office at a point of care setting.”
As Dr. Pritt said these faster tests are in very limited supply and the manufactures are struggling to keep up with demand. They are also much more expensive.
In the end, Dr. Pritt hopes that this is a learning experience for all involved.
“We learned a lot about the role the government would play in an outbreak," she said. "The importance of having adequate support of our government branches like the Centers for Disease Control and Prevention, the CDC. Having them with the power and the resources to be able to make decisions rapidly. The same thing with the FDA, the Food and Drug Administration. I think we’ve also learned that some of the extent of the regulation that’s in place can be quite challenging. We’ve seen the FDA start off with a lot of requirements for labs bringing up their own tests, and one by one the FDA has backed off on almost all of those, trying to make it as easy as possible for bringing up tests. So I think once this is all over, my hope is that government and the clinical lab community will come together and have some discussions about how this could be done better next time.”
Dr. Bobbi Pritt is a Clinical Microbiologist at the Mayo Clinic in Rochester, Minnesota. She is director of the Clinical Parasitology Laboratory in Mayo's Department of Laboratory Medicine and Pathology. Dr. Pritt also has a blog called “Creepy Dreadful Wonderful Parasites”.