Contamination caused by substandard practices at the US Centre for Disease Control caused the leading health institute to face significant delays in developing a testing kit for the novel coronavirus, according to a new report.

The CDC’s central lab in Atlanta, Georgia, was handling synthetic coronavirus material when it began assembling kits to test for Covid-19, the Washington Post reported on Saturday.

Although officials attempted to keep the projects separate, apparent cross-contamination occurred due to the close proximity of chemical mixtures featured in the kits and the synthetic coronavirus material, according to Benjamin N Haynes, a spokesperson for the CDC.

Quality control efforts “were not sufficient in this circumstance”, he told the newspaper, adding that the CDC has since “implemented enhanced quality control to address the issue”.

The Department of Health and Human Services has meanwhile launched an investigation into how the original testing kits were developed and distributed in the initial months of the pandemic — a critical time in which the country could have saved countless lives through rapid testing and containment efforts, experts said.

The CDC’s initial testing kits were then sent out to 26 labs across the country, resulting in 24 of those labs reporting false-positive cases of the novel virus.

“Only two of them got it right”, an unidentified senior federal scientist told the Washington Post, noting that contamination was the cause of the false-positive reports.

They added: “The bottom line is, if you have a negative sample, and it’s coming up positive, the only way for that to happen is cross-contamination. . . . There is no other explanation for it.”

The CDC also confirmed in a statement to the Post that issues with the testing kits may have occurred due to “a design and/or manufacturing issue or possible contamination” and that diagnostic kits are now being used in “more than 90 state and local public health labs in 50 states, the District of Columbia, Guam and Puerto Rico”.

News of the cross-contamination at CDC’s labs in Atlanta was first reported by Axios in early March, in which Food and Drug Administration Stephen Han confirmed a “test issue” had occurred.

However, at that time, the FDA commissioner blamed the problems on a “manufacturing issue”, adding: “We worked hand in hand with CDC to resolve the issues with manufacturing. FDA has confidence in the design and current manufacturing of the test that already have and are continuing to be distributed.”

The FDA commissioner said the latest tests have “passed extensive quality control procedures and will provide the high-level of diagnostic accuracy we need during this coronavirus outbreak”.

A lack of expansive testing in the initial months of the outbreak in the US, paired with a seemingly slow response to the pandemic on the part of the federal government, has resulted in significant outbreaks in states across the country, with more than 31,000 deaths resulting due to complications from the virus. Nearly 700,000 people in the US have contracted Covid-19, according to tracking data published by Johns Hopkins University.