It is six months since the first case of coronavirus was diagnosed in the US but the country is still plagued by severe testing delays, with many patients waiting for a week or more to receive their results.
Quest Diagnostics, the largest laboratory company in the US, this week warned that there was “no way” the industry could expand molecular nasal swab testing capacity in time for the autumn, when demand is expected to surge as millions of Americans catch common colds and the flu.
Why do testing delays matter?
If a patient receives a positive result after seven days, they will probably have passed the point at which the illness is at its most contagious. If they have come into contact with others during that time, they might have already infected them.
“These tests are essentially of little or even no value if they come back within that kind of a timeframe,” said Dr Tom Frieden, the former director of the US Centers for Disease Control and Prevention.
Delayed test results also make it harder for contact tracers to find and isolate people who are at risk, and mean that public health officials are fighting the pandemic with out-of-date data.
What is causing the delays?
A surge in demand in southern and western states where the disease is spreading rapidly has overwhelmed the laboratory industry, which is dominated by two large companies, Quest and LabCorp.
The increased demand comes as other states that have managed to bring down infection rates, such as New York and New Jersey, are encouraging everyone to get tested even if they do not have symptoms.
“We’ve had plenty of time to get this right,” Scott Gottlieb, the former commissioner of the US Food and Drug Administration told CBS News earlier this week. He said that LabCorp and Quest were “trying to prioritise” testing in states like Texas and Florida, which have seen an explosion of new cases.
“Not only do they fall behind in those regions, but now they’re pulling testing out of other regions and you’re seeing delays there,” he added.
Roughly 5.5m Americans are being tested each week but LabCorp and Quest are only able to process 265,000 tests a day. They have plans to expand their combined capacity to 300,000 by the end of this month, but that is still far less than is needed to bring waiting times down to a matter of days.
Why can’t the laboratory companies expand more quickly?
Quest warns it is struggling to buysupplies. At asite in California, it stores completed test swabs in an ice chest in a trailer © Bloomberg
The lab companies say there are two factors preventing them from adding extra capacity. First, they are struggling to secure supplies of reagents, the chemicals that are mixed with nasal mucus samples to determine whether a patient is positive or negative for coronavirus.
“Today, we could do more testing if we had more reagents,” said James Davis, an executive vice-president at Quest.
Secondly, the labs are struggling to buy enough testing machines from companies such as Roche, ThermoFisher and Hologic, which are dealing with a jump in demand not just from the US but also from populous countries including India and Brazil.
“We aren’t likely to see a doubling of . . . capacity over the next three months based largely on limitations of the supply base to the lab industry,” added Mr Davis.
Will more funding help?
Democrats’ attempts to include more funding for testing and tracing are being stymied by the White House © Getty Images
Democrats on Capitol Hill passed legislation in May that included $75bn in additional funding for testing and contact tracing, and even some Republicans in the Senate have endorsed the idea of additional funding. But the White House has resisted the inclusion of any more money for testing and tracing in negotiations over a new stimulus package.
Even if there were more money, it is not clear that spending it on expanding molecular nasal testing capacity would work. Private labs charge $100 per test and make chunky profits from the work. They insist that they would do more testing were it not for the problems securing reagents and machines from their suppliers.
However, extra funding could be used to develop alternatives to nasal swab tests that use a 1980s-era technology known as polymerase chain reaction (PCR).
Quest’s Mr Davis said: “What the government can do more of is to seed innovation, making sure the smartest people at the [Massachusetts Institute of Technology] and Cornell and Harvard are getting what they want and need, just like they’ve done in the vaccine industry.”
Could the Defense Production Act boost capacity?
The DPA has already been invoked to spur the production of simple components such as nasal swabs and it might also help expand the supply of chemical reagents.
However, executives in the lab industry are doubtful that it could be used to boost the supply of the sophisticated machines produced by Roche and others.
What are the alternative tests?
Antigen tests, which can quickly detect fragments of proteins found on or within the virus from a nasal swab, are much quicker and can be manufactured at scale © AFP via Getty Images
The FDA has given emergency use authorisation to two “antigen” tests that can quickly detect fragments of proteins found on or within the virus from a nasal swab. These are much quicker than the PCR tests and could be manufactured at scale to test millions of people.
However, they are not very sensitive, meaning they can produce lots of false negatives. If everybody with a negative result wanted to confirm their status by taking a PCR test, it could end up putting further strain on the system.
However, Dr Jonathan Quick, head of pandemic response at the Rockefeller Foundation, insists that antigen tests are part of the solution. “Fast and frequent beats slow and sensitive for epidemic control,” he said.
The FDA has also said it will allow Quest to conduct “pooled testing” in an attempt to speed up processing times. The method enables the lab to test four patients’ samples in the same “well” at the same time.
If the pooled sample tests negative, then all patients are informed they do not have the virus. If it tests positive, then lab technicians must examine each sample individually.