Under-pressure German COVID-19 lab produces run of false positive tests

BERLIN (Reuters) - Germany's government defended the accuracy of its coronavirus testing procedures on Wednesday, after a Bavarian laboratory delivered a run of false positives that it blamed on pressure of work and a shortage of reagents.

The MVZ Laboratory in Augsburg made wrong diagnoses in 58 of 60 tests it identified as positives over a one-week period - an anomaly that came to light after a hospital become suspicious of the results and retested the patients.

"It was not always possible to double check the positive results in a timely manner due to the high number of samples and the lack of equipment," the lab's Managing Director, Gabriele Schoen, told Munich daily Muenchner Merkur.

Deliveries failed to arrive from the lab's normal reagent supplier, forcing it to use an alternative reagent that was not compatible with its testing system, the paper said.

Government sources told Reuters the issue was not a broader structural problem, though there were isolated regional bottlenecks with reagents.

A health ministry spokesman said there was no reason to doubt the "validity and accuracy" of the PCR molecular diagnostic tests used at the MVZ lab and elsewhere in Germany.

Rigorous and accurate testing has been identified as a factor in the country's relatively low level of COVID-19 infections and deaths, but laboratory association ALM has warned for weeks that labs, particularly in big cities, were working close to capacity.

Last week, Germany carried out 1.24 million tests, up 12% on the previous week, with the rate of positive results rising to 5.7% from 3.7%, ALM said.

Germany's cabinet is working on finding ways to expand test capacities, with veterinary laboratories one possible option, government sources told Reuters.

(Reporting by Kirsti Knolle, Andreas Rinke; editing by John Stonestreet)