Health officials in the Chinese province of Hebei will review hundreds of thousands of Covid-19 tests carried out by third-party agencies after it was revealed that one laboratory allegedly hid positive cases of the disease.

On Thursday, Jinan Huaxi Medical Laboratory, which was hired to process coronavirus tests in Hebei’s Longyao County, said that some 310,000 samples taken from locals had returned negative results.

However, the lab reported the reassuring numbers to the county’s health commission before it had actually finished processing them all, the Global Times reported.

Two days later, the firm issued a correction, saying that several samples had actually tested positive.

The inconsistencies prompted an investigation into the laboratory, with local authorities saying on Sunday that they had found two confirmed cases and one asymptomatic infection in the batch of tests it handled. The head of the company was subsequently detained by police. (RT)