Federal regulators have cleared a DNA test as a first-choice alternative to the Pap smear for cervical cancer screening.

The agency acted over objections from some women’s groups and health organizations.

On Thursday, the Food and Drug Administration approved a DNA test developed by Roche Molecular Diagnostics that checks for 14 of the many types of human papilloma virus including the two — HPV 16 and HPV 18 — that cause cervical cancer.

The test is already used to confirm Pap test results, but the approval means it can be used ahead of the Pap test as a first-choice option. 

With a Pap test, the doctor looks for abnormalities in cervical cells under a microscope. The HPV test looks for DNA from the virus. Both tests require women to get in the stirrups for a vaginal swab.

After taking the DNA test, a patient who tests positive for one of the cancer-causing types of HPV would then go for a colposcopy, a more invasive test in which doctors observe cervical cells up close with a magnifying device. Women who test positive for one of 12 other types of HPV would get a Pap smear to see if a colposcopy is necessary.

“The potential benefit of [the HPV test] is that everybody that has a precancerous change or cervical cancer will have a positive test,” Dr. Kevin Ault, professor at the University of Kansas Medical Center in Kansas City, told CNN. “You’re not going to miss anybody.”

A problem with any type of HPV test is that many women will test positive for the infection, which nearly all sexually active women get at some point in their lives. Most of the time, the virus goes away by itself, but some women develop persistent infections that may turn into cancer.

But if doctors use the DNA test as the primary screening method, they can focus their Pap examinations on women who are already known to have HPV, Ault said.

A coalition of women’s and health groups — including the American Medical Women’s Association and Cancer Prevention and Treatment Fund — warn that the new test marks a “radical shift” based on insufficient data.

“We have numerous concerns about both the implications of this decision and the quality of the pivotal trial used to support it,” the groups wrote in a letter to FDA Commissioner Margaret Hamburg earlier this month. It was signed by 17 advocacy groups, including Consumers Union, the Cancer Prevention and Treatment Fund and the National Alliance for Hispanic Health.

One of the groups’ concerns with using the DNA test as a first-choice screening tool is that it cannot identify abnormalities, other than the presence of HPV, that can also cause cancer.

Cost was another concern they cited. A Pap costs about $40, while alternative HPV tests, like those made by Roche, Qiagen and others, cost about twice as much. The Pap has a good track record, too, with reported cases of cervical cancer down by 75 percent since the 1950s due in part to increased Pap screening.

Approval of the DNA test for women 25 and over is a departure from the American Cancer Society’s current guidelines, which do not recommend HPV screening for women in their 20s. Here is a summary of the guidelines from the Associated Press:

Under the latest guidelines from the American Cancer Society, a Pap test is recommended every three years for women 21 to 29 years old. Women 30 and older should have both a Pap test and an HPV test every five years, or a Pap test alone every three years. HPV screening is not recommended for women in their 20s because it increases the odds of more invasive testing that can leave the cervix less able to handle pregnancy later in life.

But FDA approval doesn’t necessarily mean doctors will use the DNA test. In a letter to the concerned groups, cited by the New York Times, Alberto Gutierrez, the agency official who oversees the FDA’s diagnostic testing, said it is up to medical societies and other organizations to decide whether and how to use the test now that the agency has cleared it for safety and effectiveness.

The Society of Gynecologic Oncology said in a statement Thursday that it is developing interim guidance on incorporating primary HPV testing into cervical cancer screening. While the new test “will provide doctors one more tool to use in cervical cancer screening,” the group acknowledeged that “approval has raised a number of questions.” It added that it is “extremely unlikely that doctors will stop using the Pap any time soon.