This news release promotes a study in the journal PLoS ONE by researchers at Philadelphia University and Thomas Jefferson University in Philadelphia. The crux: Even basic problems with the brain and other parts of the central nervous system, or CNS, are not only serious but also tough to diagnose — and especially so in rapid fashion.
According to the release, a test that uses a little cerebrospinal fluid, or CNF, gathered from a patient’s spine might help doctors quickly narrow down whether they are dealing with an infection (by a virus, bacteria, or fungus) or some other issue, such as a demyelinating disease or cancer. The key to making this possible are cytokines — tiny proteins that cells release to sound the alarm to one another — and a device that can quickly test a small sample of CNF for dozens of different cytokines and their abundances.
The release’s title does a decent job of not selling the moon, since it does not promise the “holy grail” of identifying a specific problem with one test — just the presence of an infection or something else. However, the teasing of a rapid doctor’s office-style test when one does not yet exist, and when the sample size is so small (43 people with a wide variety of issues participated) seems dubious — especially when one of its own authors says additional research is needed to confirm the core findings.
It’s also important to highlight that this early data is a “retrospective analysis,” which means that even if the sample size of patients were bigger, it would only suggest that further prospective work needed to be done to validate the testing in patients.
Problems with brains and spinal cords are often tough to diagnose. This is because infections by bacteria, fungi, and viruses can manifest similarly to other issues, like cancer or autoimmune diseases. The blood-brain barrier makes sampling the fluid that can hint at what’s going on tricky and painful — so making the most use of a sample is best.
It’s especially key with the youngest patients, whose still-developing bodies and immature immune systems may not be prepared to handle major problems like encephalitis (inflammation of the brain)and also can’t describe their symptoms.
If a one-stop test existed that could help doctors rapidly narrow down a long list of suspects for a CNS problem, it could save valuable time and financial resources, and potentially patients’ lives.
If this test can be validated it could conceivably improve speed of diagnosis in order to get the most appropriate treatment.
No costs for the test are mentioned, but a lumbar puncture can cost anywhere from about $600 to more than $2,000, with a “fair price” being about $1,000, according to Healthcare Bluebook. And this may or may not include the necessary laboratory work on the sample. (The cost of using a device called a Luminex FlexMap 3D assay, which is critical to the study, also isn’t disclosed.)
For those with robust insurance plans, only a copay may be necessary. However, those with high-deductible or significant cost-sharing (or co-insurance) plans may be in for some sticker shock.
If offices and hospitals will be required to send test samples to specialized labs for analysis that could also impact the cost.
The benefits described are put in some numerical context. The results might show the presence of an infection, or something else (like tumors or autoimmune disease). It’s seemingly innocuous, but for young children and babies, who can’t describe their symptoms, such a tissue test could be beneficial, as the release explains.
However, it would have strengthened this release to explain why some cytokine signals (and which ones) might be better indicators than others, and to what extent based on the small sample size.
Another thing that would have been helpful to explain is the fact that cytokines can also be inappropriately released (without infection, etc). This is a rare occurrence but we’d still want to know that this distinction could be made as well.
Getting a “spinal tap” to extract a sample of CNF is nothing to sneeze at.
Also called a lumbar puncture, the roughly 45-minute procedure involves inserting a needle into a patient’s lower back, navigating it between two spinal vertebrae, and barely slipping the tip into a sac near the spinal cord. This location allows a doctor to suck out the nervous system’s fluid, which is shared from the brain case down through the spinal cord.
But during or after the procedure, there’s up to a 25% chance that fluid will leak into nearby tissues and trigger headaches, according to the Mayo Clinic. Dizziness, nausea, and vomiting up to two days after the procedure can also occur, and the headaches can last as long as a week. Back pain can be an issue, too, as can bleeding at the site of the puncture.
The release rightly includes the small sample size of 43 subjects. There’s also a balancing quote from a study author that contains a vital caveat that such a test needs to be confirmed with additional research” before entering use. The closing line of the release also specifies how a larger sample population is needed both in adults and kids.
We didn’t note any sensational language.
Funding sources and potential conflicts of interest — or a lack thereof — weren’t noted in the release. The published study lists “none” under its author’s declarations of interest. In a cursory check, we also found no evidence that the authors gained to benefit from widespread use of the Luminex FlexMAP 3D assay system, which is key to the rapid analysis of spinal tap samples.
This was perhaps the weakest points of the release, since many alternatives do exist and which also use CNF. For example, the color and clarity of CNF can indicate an infection, and the presence of free-floating cancer cells typically indicate some kind of tumor.
The release would have been stronger had it brought up these and other standard-of-care procedures, noted how they work, and explained how this particular test may be better or cover a blind spot.
Although a doctor’s office test is teased, the release makes clear that it needs to be “confirmed with additional research.”
There are a number of steps ahead before we know if this will indeed be available.
If the test is validated it would add a new way to identify bacterial infection and identify it faster. The speed component is novel.
It’s clear that CNF, and perhaps the patterns of cytokines floating in it, could be a powerful diagnostic tool for doctors trying to diagnose elusive diseases of the central nervous system. The release also notes such signals could be detected early and avoid unnecessary treatments.
There was some dramatizing of the conditions and stakes of CNS problems, but nothing that struck us as unjustifiable.
Systematic, Criteria-Driven
Monday at #ADA2021, an infectious disease epidemiologist, a journalist, and a researcher shared perspectives on communication of risk in the era of COVID-19: http://ow.ly/ROfR30rMeE7 @AstleyCM @garyschwitzer @berthahidalgo @ADA_DiabetesPro
Shoutouts to @susan_bewley @drkevinknopf @MichaelBaum11 in this call for more than fawning coverage from press releases for these kinds of stories.
Also, linked history inside goes back 5 years just on Grail apparently trying to become Holy Grail. https://twitter.com/garyschwitzer/status/1408849696416841731
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