An employee at the Gwinnett Medical Center has been diagnosed with active tuberculosis and officials there say more than 100 patients may have been exposed to the disease.

Letters to those patients were mailed Friday, encouraging them to get a free skin test for tuberculosis, said Alan Bier, MD, chief medical officer for the Lawrenceville hospital. A skin test is the most common way to identify if a patient has tuberculosis.

Up to 133 patients who visited the hospital between February 1 and May 10 may have been exposed, said Bier.

Official want anyone who believes they were exposed to get tested at a healthcare facility immediately.

More details to come.