Washington(CNN) Coronavirus testing results from one of the nation's top labs were taking days longer to complete than the lab's publicly reported turnaround time, according to internal company records obtained by CNN.
On Monday, in a statement posted on its website, Quest Diagnostics said that average turnaround time for results for all patients was five days. But internal Quest Materials obtained by CNN dated the day before state that the total average turnaround time for results was 8.4 days.
Asked about the apparent discrepancy, a Quest spokesperson said the publicly reported number represented a forward-looking, "expected" figure for how long patient samples received that day would take to turnaround. The number did not reflect the actual time it took the company to get results on samples it had already tested.
In essence, the public number was a projection while the internal number reflected the reality of how long results delivered to healthcare providers on Sunday had taken on average.
The Quest spokesperson said the company shares the expected average "to allow the public to make informed decisions about where to obtain testing, before they order a test, should they find our times are too long." The spokesperson said a surge of test orders in recent weeks caused the average wait of 8.4 days shown on Sunday. On the Monday before that, Quest said the average turnaround time was seven days.
The longer reported waits at Quest come as delays in results continue to undercut coronavirus testing efforts across the US, since public health officials rely on timely results to effectively track the spread of the virus.
Delayed turnaround times can mean more lost wages for those waiting on results, and each day of delay can increase the chances that infected people may not remain isolated and spread the virus to others.
Assistant Secretary for Health Brett Giroir told NBC News Thursday that turnaround times for test results at commercial labs are overall getting quicker and that about 70% of results come back within three days, though he added, "I'm the first one to say that we want to decrease turnaround times."
The Quest materials dated August 2 also show wide variation between its test-result times in different cities and that a small percentage of results were taking about three weeks to deliver.
While Denver and Philadelphia had average turnaround times of about four days on August 2, Chantilly, Virginia, had an average of more than 13 days.
A small fraction of test results provided that day in Los Angeles and Chantilly had taken more than 20 days.
And though specimens from "priority 1" patients, who include hospital patients, symptomatic healthcare workers and others, had average turnaround times of about two and half days, specimens from the general-priority group, which accounted for 60% of the total, had average waits of about 11 and half days.
The Quest spokesperson said the company has made progress this week and is able to provide results in three days on average. Though the spokesperson added that "any significant increase in demand or constraints on supplies could cause that to slip."
In June and July, some states, labs and public health departments warned that spikes in cases led to slower results.
A spokesperson for another private lab company, LabCorp, said Thursday the company's average time to deliver Covid-19 results is two to three days. Asked about how that average is calculated, the spokesperson said it's an average of current delivery times and is "not a projection."
Quest and LabCorp each have capacity to perform about 150,000 and 180,000 diagnostic coronavirus tests per day -- more than other US commercial labs.
CNN reported on Tuesday that manufacturers of test components have warned that demand still outweighs supply, and the resulting supply shortages have reduced the number of daily samples many US labs can test.
Long waits for test results have led some experts to recommend that health officials rely more on antigen tests, which are faster but not as accurate as the lab-based polymerase chain reaction (PCR) tests.
A bipartisan group of seven governors and the Rockefeller Foundation teamed up to pursue a deal for 3.5 million coronavirus antigen tests, according to announcements earlier this week.
The pact comes as the Trump administration has faced criticism from some public health and lab officials for largely placing responsibility on states to develop their own testing plans and not coordinating a more holistic, national plan.