ZURICH (Reuters) – Some blood tests being marketed to tell people if they have ever had the new coronavirus are a “disaster”, Roche Chief Executive Severin Schwan said on Wednesday, as he prepares to launch the Swiss drugmaker’s own antibody test in May.

In developing its test, Schwan said, Roche scrutinised some existing products now on offer but rejected them as unreliable in determining if somebody has actually ever had the disease.

“It’s a disaster. These tests are not worth anything, or have very little use,” Schwan told reporters on a conference call on the Basel-based company’s first-quarter results. “Some of these companies, I tell you, this is ethically very questionable to get out with this stuff.”

(Reporting by John Miller; Editing by Michael Shields)