A better test for TB is, indeed, reason for excitement, but this story glossed over some of the limitations of the research and failed to describe the real world limitations of making an expensive test widely available in cash-strapped countries.
This was a one-sided and potentially misleading story about a rapid new diagnostic test for tuberculosis (TB). The study discussed in the article assessed how accurate the new test was, but it couldn’t tell us whether the test improves treatment or leads to better health outcomes for TB patients. So when the story speculates in the headline that the new test has the "potential to greatly improve treatment" of TB, we think this gets things off to a shaky start. The story could have recovered by also telling us why the new test might not lead to better treatment of TB. Apart from an incomplete discussion of the cost of the new test, however, this issue was not explored. As a result of this and other shortcomings, this story tilts much too far toward optimism in an area where huge challenges remain to be addressed.
Obtaining an accurate TB diagnosis can take weeks using laboratory cultures, and this delay is one of many factors that has made it difficult for us to contain the spread of this disease worldwide. A new diagnostic test that could give accurate results at the point of care would represent a critically important new tool in this fight. That’s what makes it all the more important to accurately describe both advances and setbacks in TB research.
This story does more than pay lip service to cost, flagging it as the key to making this test available in the developing world. It notes the price tag of the diagnostic machine itself and says that the $63 cost per test may be discounted by more than half in developing world countries. It fails however to compare the cost of the new test with the existing TB test. Even more important, it fails to explain that a $20 or $30 expense, which might sound modest to U.S. readers, would actually represent a huge cost burden in many developing world countries, where annual per capita health care expenditures are sometimes less than $30. A close call, but since the story made a good-faith effort to address this issue, we’ll award a satisfactory with deficiencies noted.
This story reported on and emphasized the speed and accuracy of the new test, noting its advantage in this regard over conventional TB testing. It also mentioned the test’s ability to detect TB that is resistant to rifampin — a drug commonly used to treat the condition. Nevertheless, the story never attempted to quantify the real-world implications of the research from a data-oriented perspective. Some questions we feel the story should have attempted to answer, in quantitative terms, include:
We also think the story should had paid a bit more attention to the issue of simultaneous infection with tuberculosis and HIV–something the new test could potentially help with. Tuberculosis in patients with HIV is harder to detect using current techniques, which usually involve evaluation of lung sputum under a microscope (called a "smear test"). The resulting misdiagnoses and treatment delays can be especially harmful for HIV patients given their compromised immune status. TB progresses more rapidly and is more deadly in HIV-infected individuals compared with non-infected individuals. The new test appears to be effective at diagnosing TB even in patients who had a negative "smear test" — a group that would include many HIV-positive individuals. A comment about this potential benefit would have been appropriate.
Although the new test apparently does a very good job of ruling out individuals who don’t have TB, the study reported that 5 out of 609 patients without TB received a false-positive TB diagnosis. These individuals may be subjected to additional tests and treatments that have the potential to cause harm. The story didn’t mention this.
The story calls the new study "a potentially significant advance" and "a very important discovery" — praise which appears justified — but it didn’t do enough to balance this enthusiasm with discussion of limitations. It calls the test’s expense its "one potential drawback," but a thorough evaluation could have dug up a number of other issues that merited coverage. Two key examples:
This story may be a bit misleading when it states that one third of world’s population is infected with TB. This figure includes individuals with latent or inactive TB, which is not the disease diagnosed with the new test. However, we don’t feel the story overall crossed the line into disease-mongering.
Although we wish it featured a comment from someone willing to look a bit more critically at the findings, the story did include an interview with an expert not affiliated with the study, thus meeting the minimum standard for the criterion. As far as we can tell, there were no conflicts of interest that weren’t identified.
The story notes that current testing for tuberculosis (TB) involves looking at respiratory mucus under a microscope. However, it didn’t mention the fact that there are several other rapid nucleic acid tests for diagnosing TB that are similar to the test covered in the story. These alternative tests are not as simple to conduct and can’t be deployed on a wide scale with very high accuracy. Nevertheless, making mention of these tests would have added some of the context that we felt was generally lacking in this story.
The story states the new test is available in Europe and will soon be submitted for FDA approval in the U.S. But this information doesn’t tell readers when or if the test will be available in the developing world, where need for it is greatest. In developing countries, which often have rudimentary health care systems, deployment of this test may be hampered by any number of systemic barriers. Cost is certainly one important issue. but so are management expertise and human resources and availability of reliable electricity. The importance of these issues is demonstrated in our experience with malaria and HIV, where fast and accurate tests are available but significant segments of the population do not have access to them. The story doesn’t do enough to provide this context.
We don’t think the story oversold the novelty of this new TB test, which by all accounts does represent a noteworthy advance over current methods. However, we feel the story could have mentioned that there quite a few companies working on similar tests.
Although the story does quote from a news release, it appropriately notes the source of the information. And since it includes an interview with an independent expert, we can be sure the story wasn’t based entirely on a release.