Accuracy of Lyme disease tests called into question
Accuracy of Lyme disease tests called into question
The "former Chippendales" include, from the left, standing,Terry Malaghan,Glenn Frishman, Henry Laudone, Eric Pettine, David Smith, Insu Kong, Micky Willisston, Jeff Sorensen, Les Crandall, Ray Trebisacci and John Bergeron; and foreground, from left, David Rivera and Ken Olsen. | Christine Corrigan/The Westerly Sun
June 28, 2014 11:10PM
By BETH DALEY
A growing number of tests for Lyme disease may be misdiagnosing patients when telling them that they have — or don’t have — the tick-borne illness.
An exemption in federal regulations allows many laboratories to offer Lyme tests without proof that they accurately identify the disease, leaving patients and their doctors to decide which tests to believe.
Andrew Onderdonk, a professor of pathology at Harvard Medical School who received a Lyme disease diagnosis in a federally recommended test in 2012, said that many companies are using unproven tests that can’t be trusted.
While the loophole in Food and Drug Administration regulations affects a variety of tests, it has particular significance with Lyme disease. Thousands of sick people believe they have a chronic form of the illness that can evade antibiotics and last for years, but many doctors dismiss the idea of long-term Lyme.
Fredric Silverblatt, a doctor who runs a Lyme disease clinic at South County Hospital, said he often sees patients who have been on antibiotics for years without tangible results and who have tested negative on CDC-recommended tests. In those cases, he questions if they really have the disease.
One way to resolve the controversy, he said, is “to better understand how the body reacts to Lyme.” With that will come clarity on how people are affected, and better tests, he noted.
Over the past two decades, the issue has become deeply divisive. Ailing patients are increasingly forced to negotiate between the parallel medical worlds of doctors who use only federally recommended Lyme tests that may not catch the disease early on, and “Lyme literate” doctors who may diagnose chronic Lyme, often by using alternative tests. Most insurers don’t cover those tests, which range from $100 to more than $1,000.
Federally recommended tests identify about 300,000 new cases of Lyme each year — more than three-quarters in the Northeast. In addition, medical authorities say, many other people are diagnosed with alternative tests that may be inaccurate, leading to unnecessary, inappropriate and costly treatment.
At least seven labs in the United States have been denied permission to offer Lyme tests during the past decade in New York, according to state records obtained by the New England Center for Investigative Reporting. New York is the only state that performs a rigorous review of tests before they can be offered in the state.
The labs include a Pennsylvania company that has failed to follow through on a promise to deliver independent validation studies of its test, and a Wisconsin lab whose owner was once involved in a malaria research fraud case. Officials at both labs say they stand by their tests.
The U.S. Centers for Disease Control and Prevention has become so concerned about queries from public health officials, doctors and patients regarding questionable Lyme tests — especially the Pennsylvania lab’s — that it issued a warning in May for doctors and the public to avoid tests that aren’t recommended by the federal agency.
An estimated 3.4 million Lyme tests are conducted in the United States annually largely using federally recommended tests at a cost of about $492 million, according to a recent CDC study. But it’s unclear exactly how many other tests are being done because they do not have to register with the FDA, and not all testing companies seek the stringent approval of New York.
Tens of thousands of these alternative tests are likely performed each year, the reporting center estimated, based on interviews with the CDC and two of the labs that offer tests rejected by New York.
Loophole creates market
The federal test exemption dates back to the 1970s, when the FDA began regulating diagnostic tests but exempted what was then a small group of relatively simple tests developed, manufactured and performed all in a single lab — for example, in a hospital. Many of the tests were low-risk variations of common tests, or designed for rare diseases and couldn’t be validated well in studies.
The exemption has since become a market incentive for companies that produce thousands of FDA-exempt diagnostic tests, from prenatal screening to identification of genetic mutations known to increase the risk of cancer.
The FDA announced its intention to regulate these tests in 2010, but has been opposed by many laboratories that argue that their facilities are already well regulated and the new rules would be cost-prohibitive, take too much time and stifle innovation. While many of these tests do go through robust and independent validation, not all do, making it challenging for doctors and the public to distinguish between the two.
In fact, thousands of sick people rely on the unproven Lyme tests. When the results provide a diagnosis, patients have a hope of a treatment and cure. Many say they feel better once on medication, which is further validation for them that they were diagnosed correctly.
“I did not test positive using the CDC method,’’ said Allen Bargfrede, 39, an associate professor of music business at Berklee College of Music in Boston who contracted Lyme last summer in Europe. He remembered a tick bite and a bulls-eye rash. He forgot about it until he came back to Boston and became ill with cognitive problems, overwhelming fatigue and other symptoms that CDC-recommended tests didn’t show to be Lyme.
Bargfrede ultimately received a positive diagnosis of Lyme overseas with a test that isn’t recommended by the CDC. One year later, he is recovering with the aid of antibiotics. “If there was better testing for Lyme, I could have avoided six months off from work,’’ he said.
Lyme is one of the Northeast’s most insidious public health threats, passed on by deer ticks no bigger than a poppy seed. The CDC-recommended method is far from perfect: It can miss the disease more often than it catches it in its early stages, although its accuracy improves greatly as the disease progresses. It can also tell people they are positive even after the disease is gone, according to federal health officials. Yet despite the limitations, they say a test hasn’t come along yet that has proved to perform better. So, they still recommend the tests in addition to a doctor’s judgment based on symptoms and whether the person lives in a tick-prone area.
“What needs to be done are longitudinal studies and blinded samples from a third party with no vested interest,’’ said Sam Donta, a physician and consultant at Falmouth Hospital who specializes in Lyme disease. He said the CDC test is far too strict and omits valid cases of Lyme. But he’s unwilling to use tests that are not validated. “We need something unbiased,” Donta said.
When people notice a tick bite or get sick in the summer in a Lyme-prone area, many will call their doctor. If a telltale bulls-eye rash is present, a doctor will often assume Lyme and prescribe antibiotics without testing. But not everyone gets or notices the rash, so most mainstream doctors turn to the CDC-recommended test. The two-step process first looks for increased antibodies in the blood that react to the Lyme bacteria. But because someone can test positive and not have the disease, a second test, known as a “Western Blot,” is performed to more accurately identify antibodies specific to the Lyme bacteria.
While the CDC has specific guidelines to interpret the results to identify Lyme, some labs interpret them far more liberally. IGeneX Inc., for example, a Palo Alto, Calif., lab that performs more than 20,000 Lyme tests a year, uses different interpretation criteria for the Western Blot. On its website, the lab also offers others, such as a urine test, that is not recommended by the CDC. IGeneX was rejected by New York three times for Lyme tests in the past decade for not having enough documentation to prove its tests worked. The lab didn’t respond to requests for comment.
Other labs use different means to test for Lyme. Advanced Laboratory Services Inc. outside Philadelphia, for example, says it can detect and grow the bacteria that cause Lyme — a method most Lyme researchers have never been able to reliably do. The lab has conducted more than 4,000 tests but now does less than 50 a week, according to officials there.
The facility has come under sustained criticism by scientists and regulators since its test went on the market in 2011. New York rejected it in 2012 because, the state concluded, there was no proof it worked, and inspectors who visited the facility uncovered “broad substandard” laboratory practices.
Another lab — Pharmasan Labs. Inc. in Wisconsin — has been unable to offer its test in New York, in part because of validation problems. Its test, rejected by the state last year, uses a new method to detect an immune response to Lyme.
Gottfried Kellermann, founder of Pharmasan and its sister company, NeuroScience Inc., said he plans to resubmit the rejected test to New York.
Kellermann is a German national with a 1992 felony conviction for his part in a conspiracy to defraud the federal government out of $750,000 related to malaria research.
This story was provided by the New England Center for Investigative Reporting, a nonprofit investigative reporting newsroom based at Boston University and at the studios of WGBH News.