The patient is in critical condition but remains conscious with stable life sign parameters, the department said.
Zhong Nanshan, director of the Guangzhou Institute of Respiratory Diseases, has drawn up a treatment plan for Chen. An expert team has also been set up to treat the patient.
As of 4 p.m. Saturday, local health authorities have lifted medical observation for 54 out of 96 people who were placed under medical monitoring after they had close contact with the patient.
The patient's son showed a low fever on Friday night with his body temperature hitting 37.8 degrees Celsius, according to the Guangdong Provincial Center for Disease Control and Prevention.
But he tested H7N9 negative and his fever disappeared in the early hours on Saturday, said the center.
The other people who had close contact with the woman have shown no abnormal symptoms so far.
Liao Xinbo, deputy director of the Guangdong Provincial Health Department, said after an epidemic survey, Guangdong still faces the risk of sporadic human H7N9 infections and the possibility of human-to-human infection could not be ruled out.
After Chen was diagnosed as a suspected H7N9 infection case, agricultural authorities conducted tests on samples of all poultry including 69 chickens, eight ducks and one goose at the marketplace where Chen had worked, said an official with the Guangdong provincial agriculture department.
All samples, including 25 environmental samples, tested negative for the H7 viruses, said the official.