Ms. Hickox, 33, was placed in quarantine under a new policy announced on Friday by the governors of New York and New Jersey. All people entering the United States through Newark Liberty and Kennedy Airports will now be quarantined for 21 days if they had direct contact with Ebola patients in Guinea, Liberia or Sierra Leone, even if they show no symptoms of infection.


Kaci Hickox.

Kara Hickox

On Friday night, New Jersey health officials said the nurse had developed a fever after arriving, but on Saturday, they said her blood had tested negative for Ebola. Additional tests will be conducted.

Ms. Hickox disputed that she had had a fever. She wrote that at the airport, a forehead scanner showed her temperature to be 101, but that came after four hours during which she had not been allowed to leave.

“My cheeks were flushed, I was upset at being held with no explanation,” she wrote. “The female officer looked smug. ‘You have a fever now,’ she said.”

She was eventually escorted by eight police cars to University Hospital in Newark and taken to a tent outside the building. An oral thermometer showed her temperature to be 98, she wrote.

She added that the doctor felt her neck and rechecked the temperature. “ ‘There’s no way you have a fever,’ he said. ‘Your face is just flushed.’ ”

Her complaints served as a broadside against the new quarantine policy, which goes further than recommendations from the Centers for Disease Control and Prevention. The new policy has raised concerns among some health experts and doctors that it will discourage people from going to West Africa to try to contain Ebola at its source. The World Health Organization reported on Saturday that there were more than 10,000 suspected or confirmed cases in the three hardest-hit countries.

The C.D.C. calls for self-monitoring for travelers who have had contact with Ebola patients, but not for isolation, because a patient is not believed to be contagious until symptoms appear. But C.D.C. officials said that states had the right to go beyond their recommendations.

On Saturday, in a sign of growing concern about the virus, Gov. Pat Quinn of Illinois, the home of O’Hare International Airport in Chicago, began a quarantine program similar to the one in place in New York and New Jersey. Connecticut, which enacted a similar policy on Oct. 7, has quarantined nine people who have so far showed no symptoms.

White House officials held a meeting on Saturday to discuss whether to revise nationwide policies regarding the return of health care workers from affected West African countries. An official said the administration may take further action, although it wanted to avoid anything that would hinder the ability to fight Ebola in West Africa.

On Friday, the day after a New York City doctor who had worked in Guinea through Doctors Without Borders tested positive for Ebola, the governors of New York and New Jersey described the quarantines as a necessary caution. Some of the details of where travelers would be quarantined, whether at their homes or elsewhere, were still being worked out Saturday.

Asked about the nurse’s essay while visiting Iowa, Gov. Chris Christie of New Jersey said, “My heart goes out to her because she’s someone who has been trying to help others and is obviously ill,” referring to earlier reports of a fever.

“I’m sorry if in any way she was inconvenienced but inconvenience that could occur from having folks that are symptomatic and ill out amongst the public is a much, much greater concern of mine,” he continued. “I hope she recovers quickly, and we’re going to do everything we can in New Jersey and in our public health system to make sure that she does.” In a telephone interview on Saturday night, Ms. Hickox’s father, Leon Hickox, said that his daughter “is not ill in any way.”