Traumatic brain injury biomarkers, one year in

The size of the study was large, perhaps unusually so, says Dr. Gherasim. “It was very important for the clinical team to understand the performance of this test. Ordering providers want to know when the results might be unexpected, and the more you test, the more you have a chance to encounter these cases.”

Echoing Dr. Kor­ley, she notes the importance of gaining firsthand experience with the markers, as well as collecting clinical data based on the institution’s patient population. “Clinicians need to be comfortable with a new test,” she says, especially when it’s the first of its type and the institution is an early adopter.

The sensitivity of their study mirrored that of published studies. But figuring out the appropriate who? was an important next step. The researchers then devised a smaller study to identify an implementation cohort; in this group, sensitivity was raised to 100 percent.

“We learned our population was unique,” Dr. Kor­ley says, “in that our patients were a bit older than patients in the published studies.” Part of that had to do with the study’s design, but also to the patient population of Ann Arbor. “Our median age was at least 10 years older than published studies,” Dr. Kor­ley says.

Another characteristic is that their patient population tended to be “a little less severely injured,” Dr. Kor­ley says, with the rate of positive CTs a little lower than that of published studies. “Which just reflects how often we get these CTs and how often the results are negative.”

One important finding of the retrospective study was the realization that two people with positive CTs were missed by the test. Both had a coagulopathy: One took clopidogrel, and the other had liver cirrhosis, hepatocellular carcinoma, and an INR of 1.3. “That’s a big deal,” Dr. Kor­ley says, given the high risks of allowing patients to resume their blood thinner if they have a tiny hemorrhage. “At least for now, we’re not using the tests in that subgroup of patients,” pending more data to support its use in such a high-risk group.

There are indeed limited scenarios for using these markers. They are less useful, Dr. Kor­ley says, if the injury happened more than 24 hours previously. “But if you’re able to get blood drawn within 24 hours of the injury, they’re great.”

He gives two other caveats for their use at Michigan. There is no good evidence to establish the right cutoffs for patients under 18—studies are ongoing—so he and his colleagues are not using them in this population.

Nor do they use them in patients who get what he refers to as a pan-scan—those who arrive in the ED with multisystem trauma and undergo CTs of the chest, abdomen, pelvis, etc. In those cases a head CT is also likely to be ordered, obviating the need to order the markers to inform head CT imaging.

Following the retrospective study, the test went live on Dec. 20, 2024. Dr. Kor­ley ordered the first test two days later.

The desire to become an early adopter was strong. “We understood the evidence behind using these tests,” says Dr. Kor­ley, given the institution’s involvement in some of the clinical validation work.

The clinical need for such a test was clear: to reduce the use of low-value CT imaging in evaluating patients with TBI. Dr. Kor­ley says that annually some 5 million ED visits in this country involve TBI evaluations. Some 85 percent receive CT scans, and only about 10 percent of those are positive.