The U.S. Food and Drug Administration posted a warning letter on its Web site, saying that Laboratory Corp. of America Holdings, a company that markets a test for ovarian cancer, doesn’t have the approval to sell the product.

“Because you do not have marketing clearance or approval from the FDA, marketing OvaSure is in violation of the law,” the FDA said in the letter dated Sept. 29. The letter adds that the test requires FDA’s approval before it can be marketed.A warning letter dated Aug 7 stated that marketing the test for ovarian cancer, called OvaSure, “may harm public health.”

The agency urged the company to “take prompt action” in order to “correct these violations.”

The test introduced by the Laboratory Corp., one of America’s largest clinical laboratory companies, in June promises to detect ovarian cancer at an early, still treatable stage in high-risk women. The test was developed by researchers at Yale University and it measures the level of six proteins in a woman’s blood, then calculates the probability that the woman has ovarian cancer. The five-year survival rate is 92 percent if the cancer is detected in its early stages. Only about 20 percent of cases are detected that early. LabCorp estimates that there are 10 million women at high risk.

The marketer of the test said the blood screening method was tested in over 200 ovarian cancer patients and healthy women. The test correctly classified 221 of 224 blood samples taken from participants. It identified 95 percent of the ovarian cancers. The accuracy of a negative prediction was also at 95 percent.

The Society of Gynecologic Oncologists also said that the test can be harmful for some women. The test had not been proved accurate and it may determine some women to undergo unnecessary surgeries to remove their ovaries. Oncologists say the test is too imprecise to detect ovarian cancer and additional research is needed before deciding to market it.  

The agency’s previous letter to Lab Corp. dated Aug 7 said the test is a “high-risk” one “that has not received adequate clinical validation and may harm the public health.”

LabCorp spokesman Eric Lindblom said the company was “disappointed” by the letter. He said that the company is in discussion with the FDA over the next steps, adding that they “share the FDA’s determination to assure patients are protected.”

OvaSure costs about US$220 to US$240 (S$310 to S$340). LabCorp shares fell nearly 1.8 percent to close at $60.63 on the New York Stock Exchange.

Ovarian cancer, named “the silent killer,” because it causes no specific symptoms in early stages, is the fifth leading cause of death from cancer in women and the leading cause of death from gynaecological cancer. According to the American Cancer Society estimates, more than 21,000 women will be diagnosed with ovarian cancer this year. The disease kills more that 15,000 women each year. Older women and those who have a first degree relative with the disease are at high risk of developing ovarian cancer.