Why COVID test results take so long

January 14, 2022-Omicron variants have swept the United States and are currently blaming more than 98% of COVID-19 infections, especially due to the lack of home antigen testing, in the lab. Demand is skyrocketing.

There are also increasing complaints from test takers who repeat this uneasy question.

What does it take so long to get results?

The promised duration of 24 to 48 hours is extended by a few days as people wonder if they should separate or continue their regular schedule.

Of course, the main reason is the increase in volume, but it’s not the only reason.

“You’ll be amazed at the time delay,” said Dr. Danmilner, Chief Medical Officer of the American Society of Clinical Pathology, an organization for laboratory professionals.

The journey of a nasal swab from a collection point to a test result arriving by text or email is more complex and complex than most people understand, says Milner and other experts. Many steps along the way, and other issues, including staffing and the occurrence of COVID-19 between lab staff, can delay the time required for results.

First, the volume problem

National statistics and daily aggregates from individual labs reflect the boom in test requests.

January 11, the average COVID-19 test in the United States About 2 million a day, 43% increase in 14 days.

By January 12, Quest Diagnostics, a clinical laboratory with more than 2,000 patients in the United States, has recorded 67.6 million COVID tests since its launch in 2020. 64.7 million.

The UCLA Institute for Clinical Microbiology currently processes more than 2,000 COVID tests daily compared to 700 or 800 a month ago, said Dr. Omai B. Garner, Dean of the Department of Clinical Microbiology at UCLA Health System. increase. And he doesn’t think demand has peaked.

In Tucson, Arizona, Paradigm Site Services, which provides tests under contract with local governments and companies, conducts 4,000 tests per day, but the daily total is in early November. Was 1,000 times.

Beyond volume, there are other barriers that impede the intended turnaround time.

Swab collection, pickup, transportation

“People misunderstand the whole process,” Garner says. One of the big misconceptions is that swabs are analyzed at the time of collection. This is usually not true. There may be exceptions for some rapid (and expensive) PCR test sites.

When the nasal collection is complete, the specimen is sealed in a tube and sent to the lab. It may be delivered by courier to a nearby local laboratory, or it may be shipped far away, especially if collected locally.

“Someone can be wiped with a swab, and the swab needs to go out of state,” Garner says.

Also, in heavy traffic or in bad weather, even cotton swabs transported by courier to a local laboratory can take longer than expected.

Along the way, paradigm Kelly says temperature control is important. “Samples must be stored at the proper temperature.” Couriers often store samples in coolers to transport them.

Arrive at the lab

When the swab arrives in the lab, you need to log in to the sample.

Second, the speed of the test depends on the amount of tests taken at the same time and the capacity of the lab considering the staff and equipment to analyze the sample.

Lab staffing is another factor. As the demand for testing grows, labs are struggling to add enough staff. Requirements vary from state to state, but the analysis of the test must be a trained and experienced laboratory scientist. And like any other company, the lab deals with employees who are infected with COVID-19 and have to quit their jobs to quarantine.

Potential lab employees need to deal well with high pressure situations, says Kelly. His company has hired another 30 workers in the last three weeks, bringing the total to 160. Some people work seven days a week.

Test equipment (or lack thereof) can also slow down the process.

Garner says he is often asked if fake test labs are emerging, but he says he doesn’t know anything. Also, it’s easy to verify your lab credentials.

Legal laboratories are accredited under CLIA (1988 Laboratory Improvement and Modification). Under CLIA, federal standards apply to all US institutions or sites that test human specimens to assess health or diagnose, prevent, or treat illness. CDC CLIA Lab Search Tool Search for the lab by name to confirm its certification.

The state may also provide information on certification and other exam details. For example, the COVID-19 Test Task Force in California Lab list, Details of location, number of tests performed each week, and average duration.

Lab analysis

The lab will perform two types of tests to detect COVID-19. Antigen tests detect specific proteins in the virus.

“Lab-based antigen testing isn’t much different from rapid home testing,” Milner says. There is a control line and a test line used to detect the virus.

The PCR (polymerase chain reaction) test detects the genetic material of the virus.

“RNA is extracted from the sample and purified via an extractor,” said Mariah Corbit, Compliance Manager at Paradigm Laboratories.

Special chemicals and enzymes have been added. A PCR device called a thermal cycler performs a series of heating and cooling steps to analyze a sample. PCR technology allows scientists to amplify small amounts of RNA from a sample as follows: DNA, Replicate until an existing virus is detected.

If the sample contains a virus, one of the chemicals produces a fluorescent light. The signal is detected by the PCR machine.

Dr. Chris Johnson, MD, Medical Director of Paradigm Site Services, can also provide an idea of ​​how much virus a person has with a PCR test.

Once the analysis begins, we can estimate the time it will take for the results, Milner says.

The longest analysis is the PCR test, which varies from lab to lab, but often takes about 1.5 to 2 hours. Antigen testing analysis “takes at most 20 minutes,” says Milner.

For a rapid PCR test, the results are within an hour or two, which can cost $ 300, but the processing time may be changed to get the results faster, Milner says. And in general, positive results appear faster than negative results. “Reading in real time gives good results and reports in 20-30 minutes.”

A facility that provides rapid testing may only be doing COVID testing and may be processing the test at the same location, Milner said. “If you have CLIA certification, the quality of the test should be fine,” he says.

The lab definition of non-rapid test duration may differ from that of those who are waiting for results.For example, according to Quest Diagnostics, the turnaround timeline is The end of the day Specimens are collected and end with The end of the day The results will be reported.

Verification of results

Positive results are reported as such, as are negative results. “There is no confirmation test,” Garner says. “That’s why labs need to run reliable tests.”

But if the original result is not conclusive, the test is repeated, Garner says. And what if it’s not definitive a second time? You can order another test by saying “Release as uncertain”.

Once confirmed, the results will be sent by text or email.

Long-term solution

Demand is not expected to slow in the near future and needs long-term corrections.

“From a lab perspective, we are all very frustrated and we don’t have the infrastructure and capacity to meet our needs,” Garner says. “In general, we don’t have the test infrastructure needed to fight a pandemic.”

At the beginning of the pandemic, when demand first surged, “it should have been considered necessary to build infrastructure,” he says.

Lab directors, on the other hand, know how important timely results are, but don’t sacrifice speed for accuracy. “We want to make sure it’s done correctly,” says Kelly.

Why COVID test results take so long

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