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CNN wrongly reports that a new blood test can “help detect concussion”


3 Star


FDA approves first blood test for concussion

Our Review Summary

This story managed to earn three stars despite grossly misleading readers.

It reports the FDA’s approval of a blood test to detect biomarkers associated with brain lesions, which the FDA says will eliminate the need for a CT scan in at least a third of suspected concussions. The story covers cost and availability and usefully points out that this test hasn’t been approved for kids.

But the lead gets it wrong when it says the test is designed to “help detect concussion”; it’s not. The test is designed to detect structural brain injuries that might be picked up by a CT scan, such as skull fractures or bleeding in the brain.

The story also doesn’t address uncertainties with the quality of evidence or potential harms. Finally, it misses an opportunity to educate the public about the need for more judicious use of CT scans, which are not helpful for detecting concussions.


Why This Matters

Greater understanding about the short- and long-term consequences of head injuries has generated a lot of interest in how to detect and treat them. That was no doubt a factor in the widespread coverage of the FDA’s approval of this test.

CNN wasn’t the only news outlet to get this story wrong, but that’s no excuse. Widespread misreporting of this test as a way to detect concussion could lead to harms, such as people being falsely reassured if they undergo this test and get a negative result.

It’s also important for news stories to reinforce the appropriate use of CT scans. According to Choosing Wisely, CT scans “cannot show if you have a concussion.” Only a doctor can diagnose a concussion, based on a face-to-face evaluation. A CT scan — and presumably this new test — can detect a skull fracture or bleeding in the brain.

Finally, news stories should flag weaknesses in the evidence used to support regulatory approvals, particularly for tests that are fast-tracked.


Does the story adequately discuss the costs of the intervention?


The story quotes Hank Nordoff, chairman and CEO of the company that makes the device, on the anticipated cost of the blood test compared with the cost of a CT scan: “Where a CT scan can cost $800 to $1,500, Nordhoff predicts that the new test would cost closer to $150.”

A neutral source on the price of CT scans would have been better, but that doesn’t appear to be far off the mark.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The story blunders when it states, “When compared with a CT scan, the blood test was 97.5% as effective in detecting concussion and 99.6% effective in ruling out concussion.”

In fact, the figures pertain to detecting brain lesions, not concussions.

It also states the most significant purported benefit: “The FDA believes that using the new blood test, imaging can be avoided in at least a third of patients who are suspected of having a concussion.”

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

Presumably the risks associated with this biomarker test are quite small, but this is not stated in the story.

There is no discussion of the potential harms of using a biomarker to rule out the need for a CT scan. For example, might some people who get a negative reading mistakenly think that means they don’t have a concussion? Would false positives lead to unnecessary CT scans or other intervensions?

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

We wish the story had done more to flag uncertainties about the quality of the evidence.

For example, while the FDA asserted that the test would reduce the need for CT scans, it’s unclear whether it will in practice. Reducing scans could be a challenge if other forces that compel their use — including clinicians’ fears about missing a clinically significant injury — aren’t addressed.

Further, the story’s reference to the fact that the biomarker test has been approved by the FDA might give readers the wrong impression that there were rigorous clinical trials. There’s no mention that the new breakthrough devices program under which this product was approved allows the FDA to accept what many consider to be a lower standard of evidence than what’s historically been required.

The story says the FDA evaluated a clinical study of 1,900 blood samples from people thought to have concussion or mild traumatic brain injury. It also refers to “clinical trials,” but no clinical trials are mentioned in the FDA’s news release.

This could be confusing to readers, who might not understand that what appears to be an observational “study” of available blood samples does not match the rigor of a clinical trial. The FDA’s news release does not contain details about how the data was gathered or analyzed, and some researchers have raised concerns about the evidence supporting the blood test.

On the positive side, the story does mention that a separate test has yet to be developed to detect damage from repeated hits.

Does the story commit disease-mongering?


Head injuries, traumatic brain injuries, and concussions are often in the news. This story appropriately addresses the seriousness of the medical condition.

The story also contains this data: “According to the US Centers for Disease Control and Prevention, there were approximately 2.8 million incidents involving traumatic brain injury emergency department visits, hospitalizations and deaths in 2013.”

Does the story use independent sources and identify conflicts of interest?


There’s input from a neurologist, David Dodick, MD, who appears to be an independent source.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

There’s no discussion of alternative strategies to decrease the use of CT scans, such as better educating parents and clinicians about their appropriate use.

Does the story establish the availability of the treatment/test/product/procedure?


It is fair to assume that with the FDA approval of the biomarker test some hospitals may begin trialing its use. This may not be widely available anytime soon, but it is reasonable for the public to be informed about the existence of the test.

The story quotes the CEO of the company that makes the test as saying it “would be available to hospitals,” and “he hopes a handheld sideline device could be commercially available in the near future.”

Laudably, the story states in the lead that the test has been approved for adults, which is significant because many kids are suspected of having concussions while playing sports. It further states that the study supporting the device’s approval did not include data on children, though the company “plans to include them in future studies.”

Does the story establish the true novelty of the approach?

Not Satisfactory

The story states this is the first time the FDA has approved a blood test to “help detect concussion in adults.” Actually, the test does not detect concussions; it detects biomarkers for brain lesions.

Does the story appear to rely solely or largely on a news release?


The primary content in the story was found in an FDA news release, but the reporter did supplement the story with additional reporting. However, in this case, we wish the story had stuck more closely to the wording of the news release for the sake of accuracy.

Total Score: 5 of 10 Satisfactory

Comments (1)

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Rob Oliver

February 21, 2018 at 1:03 pm

Excellent summary. The mainstream treatment of this story missed the whole idea that a concussion is a clinical diagnosis without any characteristic on CT scan. The blood test would be used after the fact to confirm or exclude significant TBI.