Michelle Andrews / Special to The Washington Post

No one looks forward to screening tests for colon and rectal cancers. But under the Affordable Care Act, patients are at least supposed to save on out-of-pocket costs for them. Coverage is not always clear; however, and despite the federal government’s clarifications, consumers still have questions.

Under the law, most health plans are required to cover a range of preventive health services without any cost-sharing by patients if the services are recommended by the U.S. Preventive Services Task Force, an independent group of medical experts. (The only exception is for health plans with grandfathered status.)

The task force recommends colorectal cancer screening for most adults starting at age 50. These tests include colonoscopy, sigmoidoscopy and fecal occult blood testing (which examines the stool for traces of blood).

A colonoscopy is the most thorough of the screening tests and is favored by many clinicians. About half the time, polyps are discovered and removed during the test to determine whether they are cancerous. This removal can create billing problems, says Katie Keith, a research professor at Georgetown University who co-authored a report on screening colonoscopy coverage under the Affordable Care Act.

According to the study, some insurers judged that a colonoscopy with polyp removal was a therapeutic rather than a screening procedure, and subsequently billed patients for some or all of the test’s cost, which can reach $2,000 or more.

In February, the Obama administration stated that for people in group and individual health plans, polyp removal during a screening colonoscopy was an integral part of the screening test and should be covered without patient cost-sharing. However, the guidance doesn’t apply to Medicare beneficiaries.

Other screening coverage questions remain murky. What happens, for example, if someone gets a positive result on a fecal occult blood test? In that case, the task force says a colonoscopy is required to examine the colon. But insurers vary in whether they consider such a followup colonoscopy a separate diagnostic test, according to the report by Keith and others, including the Kaiser Family Foundation.

“In many communities, stool testing may be common because people can’t get an appointment for a colonoscopy for months,” said Robert Smith, senior director of cancer screening at the American Cancer Society, another co-author of the report. “If they have a positive stool test, they face the uncertainty of what it would cost to get the colonoscopy.”

People who are at higher risk for colon cancer because of family history or their own history of polyps also face a gray area in cost-sharing. These patients are often advised to get a colonoscopy more often than every 10 years, the recommended frequency for people at average risk. In February, the federal government clarified that high-risk patients could qualify for more frequent screening without cost-sharing.