With COVID-19 cases spiking around the country, laboratories have struggled to keep up with increasing demand for molecular SARS-CoV-2 testing.Executives at leading national labs acknowledged during recent earnings calls that test capacity challenges are likely to become more severe in coming months as schools and businesses reopen and seasonal respiratory viruses mix with what some anticipate could be another wave of COVID-19 infections.”I think we’re going to need all the capacity we can get to get through the fall,” Adam Schechter, Labcorp’s chairman and CEO, said on the company’s earnings call this week. “We don’t know for certain what the fall will bring, but as schools open up, as businesses open up, and as the fall flu season comes to fruition, I think we’re going to continue to do more testing.”While many researchers and labs are exploring alternatives to PCR to help meet testing needs, Schechter said he believes that PCR will remain the gold standard for diagnosing active SARS-CoV-2 infections.”Therefore, we will continue to build capacity as fast as we can and overcome some of the issues that we face in terms of supplies and machinery,” he said.National reference labs including LabCorp, Quest Diagnostics, and Opko Health subsidiary BioReference Laboratories, ramped up their molecular SARS-CoV-2 testing capacities throughout the spring and at one point in late April and early May even found themselves with unused test capacity. Loosening restrictions around who is eligible for testing along with a rapid rise in case numbers throughout the South and Southwest have reversed that situation, though, with these labs now reporting significant backlogs and slower turnaround time.Quest this week issued a statement saying that turnaround times for molecular SARS-CoV-2 testing currently stand at more than two days for high priority patients and more than seven days for all other patients. According to its website, LabCorp’s average turnaround time is two to three days from the date of specimen pick-up with faster turnaround for hospital patients. BioReference said that molecular SARS-CoV-2 test results are typically available within three days after the lab receives the sample.Some observers have questioned the current value of molecular testing given these turnaround times. In a recent Twitter post, Michael Mina, assistant professor of epidemiology at Harvard University’s T.H. Chan School of Public Health said that tests with a turnaround time of six-plus days “should not even be offered.”The challenges in rapidly growing molecular SARS-CoV-2 test volumes are substantial, Steve Rusckowski, Quest’s chairman, CEO and president, said on the company’s recent earnings call.He cited as limitations not only obtaining instrumentation for running the tests but also for extracting RNA and doing the required liquid handling steps, adding that the company was “working with all [its] suppliers to get as much as we can get.”He noted as well that getting new instrumentation physically into place and up and running “takes some time.”Personnel is also a limiting factor.”This is a microbiology department that has gone from the backwater of the laboratory to front and center, and we have capacity limits around the people and those that are trained adequately to deliver on this,” Rusckowski said.As has been widely reported, testing reagents are also an issue, “and so we’re working actively to get [vendors] to first of all give us more, and secondly to be reliable in what they commit to delivering to us,” he said.Quest CFO Mark Guinan said that concerns about overinvestment in molecular capacity was not an issue, however.”The challenges are not financial or willingness to spend more capital or [in] operational expenses to get things up and running,” he said. “There is no hesitancy to add capacity because of uncertainty in demand.”LabCorp’s Schechter expressed similar sentiments.”We are building as much capacity as fast as we can,” he said. “I have no constraints on buying machines and buying reagents. We are working with our suppliers, who have been just terrific to work with, to build whatever we need.”Even so, the expansions in capacity these companies are targeting seem unlikely to be enough to cope with a large fall surge in demand. LabCorp, for instance, is aiming to push its current capacity of 150,000 tests per day to around 180,000. Quest is aiming to push its capacity from a current level of 135,000 tests per day to 185,000 by Labor Day. On Opko’s earnings call this week, BioReference Executive Chairman Jon Cohen said the lab currently has a molecular SARS-CoV-2 test capacity of 50,000 tests per day and that it plans to double this in the next several weeks.Opko CFO Adam Logal said on the call that, like Quest and LabCorp, BioReference’s testing volumes had been limited by the availability of reagents and consumables used in PCR assays.”Demand continues to build day over day or week over week, but… the supply chain constraints that we’ve been faced with have limited our ability to really expand our testing capacity,” he said.Opko CEO Philip Frost also noted that the company has tried to “modulate” demand for its tests to prevent a backlog that would negatively impact test turnaround time, with Cohen adding that the company is “incredibly sensitive” to the goal of maintaining 72-hour turnaround.Approaches like pooled testing could help handle rising test volumes. Both Quest and LabCorp received emergency federal approval this month for pooled molecular SARS-CoV-2 testing.Schechter said, however, that while pooling would be “an important piece” of the company’s testing plan, it would not be “the primary piece.””We will not be rolling out pooling to all of our labs,” he said. “It takes a lot of technical capabilities to do these analyses, to hold the samples while you test all the samples. It’s a lot of work and you need some specialized equipment.”He added that it had to be used in the right patient populations, as well. If used in populations with too high a prevalence, high rates of positives in the initial pooled testing round can make the process counterproductive.Rusckowski likewise emphasized that pooling would prove most effective in low prevalence areas.BioReference has also begun to use pooling, with Cohen noting that the company has been working through the process of validating and receiving EUA for the approach on its different testing platforms. He also highlighted the importance of targeting the method to low prevalence regions.In another development that could help expand capacity, Quest announced this week that it received emergency federal approval for an approach that speeds extraction of viral RNA from patient samples.Schechter suggested LabCorp would also consider using next-generation sequencing to scale SARS-CoV-2 testing.The question, he said, was “at what cost, at what price point, and how accurate will it be versus the PCR testing? If there is something that makes sense, we are going to look at it.”He said, however, that he believed that “PCR testing as we go into the fall is going to be critical, and that is why we are so focused on trying to build capacity.”This story first appeared in our sister publication, 360Dx, which provides in-depth coverage of in vitro diagnostics and the clinical lab market.