BNP Chairperson Khaleda Zia tested negative for Covid-19 last night and her condition improved slightly.
"Madam's [Khaleda] coronavirus test came negative tonight," hospital sources told The Daily Star.
Even though her health condition has slightly improved, fluid was being extracted for her lungs, doctors said.
Her oxygen saturation level remains 100 percent with support and she requires less than a litre of oxygen per minute, they added.
Seeking anonymity, a doctor of the 10-member medical board for Khaleda, said her dependency on oxygen support has decreased largely.
The former prime minister has passed critical times on Wednesday and Thursday. Her condition started improving from Friday.
The doctor said, "She [Khaleda] is stable now but her stability needs to be continued for the next few days. She may fly abroad if her situation continuously improves."
Her blood pressure is normal and blood sugar under control though it went up to 26, the doctor said.
Meanwhile, Khaleda's family members have talked with a private hospital in London and two hospitals in Singapore.
Family members have already talked with National University Hospital and Mount Elizabeth Hospital for Khaleda's treatment.
According to sources, Khaleda's family members were now waiting for the government's permission. Once they get it, they would complete the rest of the procedures.
To take Khaleda abroad, her brother Shamim Iskandar wrote to the home ministry seeking approval on Wednesday night.
But till yesterday the government did not give any decision in this regard.
Khaleda did a medical checkup in Singapore before her imprisonment, and if the government of the city-state allows, she might be flown there.
Khaleda was admitted to Evercare Hospital on April 27, three days after she tested positive for coronavirus for a second time.
She first tested positive for the virus on April 11. She also has arthritis, diabetes and eye problems.
She was taken to the hospital's Coronary Care Unit (CCU) with breathing difficulties on Monday afternoon.
The government released Khaleda from jail on March 25 last year, suspending her sentence as per section 401 (1) of the Criminal Code of Procedure.
The suspension was later extended twice.
The BNP chairperson landed in jail on February 8, 2018, after a special court sentenced her to five years in prison in the Zia Orphanage Trust corruption case.
On October 30, 2018, the High Court raised her punishment to 10 years.