Medical authorities of east China's Anhui Province confirmed Wednesday that 19 renal patients have been infected with hepatitis C after receiving dialysis at a hospital in Huoshan County.

A blood test reinspection of 57 dialysis patients by provincial medical diagnostic center confirmed that 28 of them were infected with hepatitis C. Nine of the 28 had contracted hepatitis C before receiving dialysis, said Lu Shitang, deputy director of county health department and head of a special team to investigate the incident.

Earlier blood test in the county hospital had indicated 25 of the patients were infected with hepatitis C.

The patients infected with Hepatitis C would receive free treatment at the county hospital. "Free medical examinations would also be carried out for the patients' family members," Lu said.

Medical experts are discussing treatment plans for each patient based on their blood tests, Lu added.

"Hepatitis C has a latent period from two weeks to half a year on its virus carriers. There were possibilities that the patients had been the disease carriers before taking dialysis in the hospital," said Zhu Yunwu, deputy head of the hospital.

He said the dialysis patients had serious kidney illnesses and were vulnerable to infectious diseases.

"Systematic management and better surveillance can cut the infection rate, but it's difficult to guarantee a zero rate of infection in dialysis, when blood passes through the machine to remove toxic substances," he said.

Provincial health authorities are still investigating the cause of the incident.