A hospital visited twice by a Utah woman who died Saturday of H1N1 swine flu complications said Monday it acted properly in caring for her.

In a statement, Jordan Valley Medical Center said it cannot comment on the specific case but added that for any patient with the virus, "we can confirm that all established CDC guidelines are followed during their course of treatment."

Two rapid diagnostic tests conducted by the hospital indicated Francine Rushton, 47, did not have the flu. So she did not qualify for antiviral medication under state and federal guidelines -- despite the rapid test's high false-negative rate, her flu-like symptoms and her contact with her mother, who did have a confirmed case.

The Utah state epidemiologist, while not commenting specifically on the woman's case, said Monday doctors need to exercise their own clinical judgment rather than relying strictly on the test or treatment guidelines.

The H1N1 flu is now so widespread in Utah that a person with a fever, cough and sore throat can be presumed to have the flu unless there is some other obvious explanation, said Robert Rolfs, of the Utah Department of Health.

"If that person also was exposed to somebody who has influenza it makes it even more likely they have influenza," said Rolfs. "At this point, it's common enough I think it is quite reasonable to treat them [as a flu patient] whether or not that rapid laboratory test tells them they have influenza."

Rolfs also said that anyone who tests positive for Type A influenza, "it really tells you they have the H1N1 virus because that is all that is circulating right now."

And someone sick enough to be hospitalized should be treated, he said.

Rushton, 47, became ill a day after her mother was positively diagnosed with the flu on May 30 at an urgent care clinic. Rushton, who was living with her mother, visited the same clinic but was told her flu test was negative, said her brother Craig Whitehead.

"They got sick at the same time, within 24 hours," he said.

Three days later, Rushton went to Jordan Valley Medical Center but a second test came back negative. She was sent home and told to drink fluids and rest, her brother said.

"We begged the doctors to treat her with [the antiviral] Tamiflu because it had helped her mother, but they refused because her test had come back negative," Whitehead said in a statement. He said Monday that physicians there "didn't think them living together, eating together was big enough factor to treat her."

Rushton continued to deteriorate and three days later returned to Jordan Valley, where she was admitted. But a third test for the flu again was negative.

She was transferred to Intermountain Medical Center in Murray on June 9 in critical condition. A day later, a test for Type A flu finally registered positive and a day later further testing confirmed Rushton had H1N1 flu, Whitehead said. But it was too late to save her.

"IMC hospital -- we want to thank them, they did a great job," he said. "We love the effort put out to help her. The shock and trauma unit was unbelievable in trying to save her life."

So far, four Utahns who have contracted the H1N1 flu have died. The state had registered 688 confirmed cases statewide as of June 12.

The rapid influenza antigen test used in health clinics and doctor's offices to make an initial flu diagnosis has a sensitivity rate of 50 percent to 70 percent compared to viral tests done in a lab, according to the CDC.

"However, much lower sensitivities have been reported," said Tim Uyeki, a physician with the CDC's influenza division. "False negative results clearly occur. This means that a fair amount of infections are missed by this test."

Rolfs said that "depending on the test, depending on the situation, [the test] may miss half of the people who have it. So those tests are not perfect."

False negative results are more likely when disease prevalence is high, the CDC said.

"Clinicians may consider using rapid diagnostic tests as part of their evaluation of patients with signs and symptoms compatible with influenza, but results should be interpreted with caution," the CDC said in a May 2 report.

The brief said the H1N1 flu cannot be excluded based on a negative rapid antigen test, and that in patients who have had contact with someone with a confirmed case of the flu additional testing and treatment may be warranted.

Current CDC and state health department guidelines current recommend use of the antiviral medication only for high-risk patients, even when close contact with someone with a confirmed case has occurred.

Uyeki said in an e-mail to the Tribune that transmission of the new virus is not completely understood. "There are many unanswered questions about this virus that CDC scientists and others are working to address," he said.

Rolfs said health care officials don't know what to expect from the virus next flu season.

"Some of the past pandemics have started out like this -- relatively mild -- and become much more serious," he said. "But there have also been times when it started out like this and didn't get much more serious. We are preparing in case it does get worse. I hope it doesn't."

brooke@sltrib.com