Dozens of nursing home residents had to be retested for the coronavirus after problems were found with their initial tests, WBAL-TV 11 reports.

Joe DeMattos, president of the Health Facilities Association of Maryland, said the tests were returning false positives. Nursing homes have been testing patients on a weekly basis since late spring.

"Most skilled nursing and rehab centers in Maryland have had weekly tests that have resulted in one or two positive results. And in last week's batches, in these nursing homes, they popped 20 to 30 positive results. So that was way out of sorts," DeMattos said.

When facility operators had the results retested, most came back negative, he said.

"The real danger is getting a false positive and then moving somebody -- who is ultimately negative -- into a room or part of a center where there are positive patients and needlessly exposing someone who is negative to someone who is positive because you have a false positive result," DeMattos said.

The tests were conducted between Sept. 2 and 8. Those who are being retested got the new tests at no cost. State health officials supplied the University of Maryland School of Medicine lab with 370,000 coronavirus tests to deploy to nursing homes. Read more at WBAL