The Food and Drug Administration approved for marketing a blood test that uses the presence of certain proteins to predict whether adults with a suspected concussion have structural brain injury, and which could conceivably reduce the number of people who undergo costlier computed tomography (CT) scans. The Brain Trauma Indicator test measures levels of proteins, known as UCH-L1 and GFAP, that are released from the brain into blood and measured within 12 hours of head injury. Its anticipated that knowing these levels can help predict which patients may have intracranial lesions visible by CT scan and which don’t.
We wish the release had included the research institutions involved and any publications relating to the study so that we could evaluate the evidence.
This evidence was also missing from a CNN story we also reviewed on the test.
There were approximately 2.8 million traumatic brain injury (TBI) visits to the emergency department in 2013, according to the U.S. Centers for Disease Control and Prevention, and of these, TBI contributed to the deaths of 50,000 people.The release predicts that about one-third of patients may be able to forego CT scans because of this test’s predictive value. While the blood test reportedly has high sensitivity and specificity, logistical issues may lead doctors to do the test and continue to scan. Emergency department doctors may not be able to wait at least 3-4 hours for the blood test results since this would impact other workflows.
News releases about concussion are bound to get a lot of attention. In this case, the news release doesn’t clearly spell out to lay readers what this test does. It’s not a test for concussion, as a casual reader might glean from the way it’s worded.
The release notes the cost of CT scans as if the blood test costs nothing. In reality, the blood test could cost more than the CT scan (plenty of blood tests already do) and the comparison drawn is meaningless. The release should have noted whether the blood test could be done in a standard lab or would require specialized techniques, which would affect cost, and how the 3-4 hour minimum timeframe to process the blood work would realistically impact the workflow in emergency department settings.
We applaud the release for at least acknowledging cost concerns.
“…availability of a blood test for mTBI/concussion will likely reduce the CT scans performed on patients with concussion each year, potentially saving our health care system the cost of often unnecessary neuroimaging tests.”
But there’s no cost data given to back up that assertion.
The release refers to a multi-center prospective study of 1,947 blood samples, but does not tell us the citation for publication of that study. The blood sample tests were able to “predict the presence of intracranial lesions on a CT scan 97.5 percent of the time and those who did not have intracranial lesions on a CT scan 99.6 percent of the time. These findings indicate that the test can reliably predict the absence of intracranial lesions.”
The release claims that the blood testing will rule out the need for a CT scan in “at least one-third of patients who are suspected of having mTBI.” This is the main purported benefit, along with reducing costs.
The Brain Trauma Indicator was able to predict the presence of intracranial lesions on a CT scan 97.5% of the time and those who did not have intracranial lesions on a CT scan 99.6% of the time. These findings suggest that the test can reliably predict the absence of intracranial lesions and that health care professionals can incorporate this tool into the standard of care for patients to rule out the need for a CT scan in at least one-third of patients who are suspected of having mTBI.
The release does not mention harms. In any screening test, there is always the harm of missing an injury that exists or finding a false positive that leads to unnecessary and sometime costly followup tests and treatments.
The release does a good job describing the results of a multi-center prospective clinical study of 1,947 individual blood samples from adults with suspected mTBI/concussion and reviewed the product’s performance by comparing mTBI/concussion blood tests results with CT scan results. But it missed an opportunity to share the trial results in a transparent fashion. The “study” appears to draw on data that was already available from a clinical trial. That isn’t the same as conducting a randomized clinical trial on the blood test, and that’s not explained in the news release. There’s no mention of the name of the trial or where it had been published. A glowing quote from the FDA commissioner is no substitute for peer-reviewed trial results. There’s no explanation for how the FDA arrived at the assessment that the test could “rule out” CT scans in a third of suspected concussion cases, which is the main purported benefit of this test.
There is no outward disease-mongering but the information about deaths from TBI seemed a bit over-the-top since the population targeted by this test have potential mild TBI which would be unlikely to kill.
The release doesn’t name study funders.
The release explains very well the typical ways that a brain injury is evaluated in an emergency department. It compares these blood tests with the existing standard, a CT scan.
The release announces that the test is “approved” for use, so we assume it will be widely available. It also quotes an official who says the test “can be used both in the continental U.S. as well as foreign U.S. laboratories that service the American military.”
The FDA states that the blood test is a first of its kind to be approved for marketing.
We did not identify any unjustifiable language. The purpose of the test is somewhat mis-characterized, though, as a test for evaluating mild TBI, when in reality it is designed to diagnose intracranial lesions or structural brain damage.