Mae Mah, a 51-year-old Richmond, B.C., woman who died from the H1N1 virus Nov. 1, went to the hospital twice in the 48 hours before her death -- and was sent home each time.

Her family claims Richmond Hospital was negligent.

"This shouldn't have happened. The hospital was negligent not to do something about it. They should have done something. If they did, she would probably still be here," her daughter, Tiffany Yung, told CTV News Tuesday.

Mah was looking forward to marrying her boyfriend and was in the middle of organizing a birthday party for Yung, her oldest daughter.

But on Oct. 31, Mah, who suffers from asthma, was having trouble breathing. Her inhalers, which she used daily, weren't helping.

She went to Richmond Hospital.

After about an hour, her family says, Mah was treated and sent home.

The next day, Nov. 1, Mah was taken to hospital by ambulance -- again with breathing problems, as well as a fever and sinus congestion.

After about five or six hours, she was treated and sent home again -- with Tylenol.

"She called me and said, she wasn't dead yet," Yung said. "That was the last thing she said to me. I didn't hear back from her."

Later that day, Mah went into cardiac arrest at her apartment and died in hospital.

Two days later, the family learned that Mah had been stricken with the H1N1 virus.

"She didn't know she had it," Yung said. "The hospital didn't know either. They didn't bother checking and just sent her away."

Mah's family insists doctors should have recognized the problem.

An H1N1 expert says diagnosing the virus in asthmatics can be difficult. Symptoms can calm down and then spike up unexpectedly.

But Dr. Anand Kumar said given the current pandemic, and the fact viral infections tend to make asthma worse, he'd err on the side of caution.

"It doesn't specifically say H1N1. It does say there is something you want to pay attention to, that there may be more going on than just a routine asthma flare," he said.

Vancouver Coastal Health is investigating.

In an email, a spokesperson said, "We are reviewing the chart of this patient, but can confirm that she was seen by emergency physicians on each occasion she visited the emergency department."

At a media briefing Tuesday, Dr. Perry Kendall, B.C.'s provincial health officer, said he had no information on the case.

Yung said Mah's boyfriend is a "total mess."

"My mom was everything to him," she said.

Yung said her birthday is next Monday.

"My mom had a surprise party planned for me. It's really devastating she won't be here to celebrate."

With a report from CTV British Columbia's Leah Hendry