NEW YORK – After receiving 510(k) clearance from the US Food and Drug Administration earlier this month for its I-Stat TBI cartridge for use with whole blood, Abbott plans to further expand its existing portfolio for traumatic brain injuries into new settings.
The test, which was developed in collaboration with the US Department of Defense, has been in the works for the past decade, along with many of Abbott's other TBI tests. All of Abbott's tests, including the I-Stat assay, utilize two biomarkers linked to head injuries: glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase L1 (UCH-L1). Both biomarkers are specific to the brain and are released into a person's bloodstream after experiencing a head injury, even a mild one, said Chris Davlantes, senior director of global medical and scientific affairs for Abbott's point-of-care business.
The immunoassay combines both biomarkers in one cartridge for the I-Stat point-of-care analyzer and includes an algorithm that determines whether either marker is elevated above a cutoff point. If neither is elevated, the test returns a "not elevated" result, but if one or both markers are elevated above that cutoff point, the test can provide a quantitative value for both biomarkers. Depending on how elevated the markers are, the test "may detect concussions that we previously weren't able to visualize even on MRI," Davlantes said.
While there are other biomarkers that can be used to detect brain injuries, such as s100, Davlantes said they may not be as effective because other injuries outside of the brain can elevate them. For GFAP and UCH-L1, there are "very few things that will make [them] elevated when there's not a brain injury," and those things would only slightly affect specificity, not sensitivity of the test.
In 2018, Banyan Biomarkers received FDA marketing authorization for its Brain Trauma Indicator, which utilized the same biomarkers as Abbott's test. However, Abbott nonexclusively licensed the biomarkers in 2019 after receiving a $32.5 million contract extension from the US Army to develop a blood-based concussion test.
The current typical standard of care to determine whether someone has a concussion is a physical examination, patient history, and the Glasgow Coma Scale, a clinical scale that assesses a person based on their ability to perform eye movements, speak, and move their body. A mild TBI is defined as someone with a Glasgow Coma Scale score between 13 and 15. The majority of patients suspected of having a TBI also receive a CT scan, but Davlantes noted that a CT scan is "not really the gold standard [for] ruling in [or] ruling out a concussion."
A blood test is "a lot more sensitive than imaging" in many cases because it detects the brain injury at the cellular level and provides "more objective data," he added. Abbott's test is intended to be used to rule out the need for a CT scan — if someone receives a normal result, clinicians don't have to order a CT scan for that patient.
Davlantes noted that right now, the test is only cleared for use in patients 18 years or older with suspected mild TBIs to rule out the need for a CT scan but said that the GFAP and UCH-L1 could potentially have prognostic value in moderate to severe brain injuries and help determine their severity. Research published in the Lancet Neurology in 2022 found the test could be used to predict death and disability in patients with head injuries, and the company is continuing to research the test's potential prognostic implications.
A different version of the test, the I-Stat TBI Plasma Assay, received FDA clearance in 2021 for a similar use case on the same I-Stat Alinity instrument but was cleared only for use with plasma and within 12 hours of the suspected TBI. The new test cleared earlier this month is approved for use with whole-blood samples and in patients who have had a suspected head injury in the past 24 hours, widening the ability to use the test.
Abbott also offers its Architect and Alinity I laboratory-based tests using the same biomarkers for plasma and serum, but the new I-Stat TBI assay has "roughly the same performance" as the laboratory tests without the need to centrifuge blood samples, Davlantes said, speeding up the testing process and making it more accessible. By using whole blood, the test is "truly point of care" and can be used in urgent care centers, free-standing emergency departments, and nursing homes, among other settings, he said.
In places that don't have a CT scanner, it could also be useful in determining whether to transport someone to the hospital, he added.
The test will still need a CLIA waiver to be conducted on athletic fields or for soldiers on the battlefield, but "that's where we're heading," according to Davlantes. The company also plans to expand the indications to rule-in concussions, capillary fingerstick blood, and pediatric patients. Abbott is conducting ongoing research in these areas, and Davlantes said that the rule-in concussion indication is its next step.
On a conference call discussing the company's financial results last week, Abbott CEO Robert Ford said that the opportunity for the test is twofold. There is a "market conversion component" because the I-Stat already has a good position in the point-of-care market, and this test can find a place in that space. There is also, he noted, a market expansion opportunity as the test continues to be developed for other indications.
Once the test can be used with a finger prick sample, it can be taken "even closer" to settings that need a rapid concussion test, such as universities and high schools. Although there's "more work to be done in terms of the product and the claims and the trials," Ford said the company is expected to see "nice growth" in the segment.
The other versions of the TBI test will remain available, a spokesperson for Abbott noted via email. The continued availability of the tests "across both our core and point of care platforms offers clinicians a comprehensive set of diagnostic options to assess patient conditions."
Although the test doesn't currently have a billing code associated with it, Davlantes noted that it can be included in a bundled payment in the emergency department and that not being able to bill for the test specifically is "not necessarily a deal-breaker for most clinicians."
While he declined to share the exact cost of the test, he noted that it is "much cheaper than a CT scan" and that the benefits of shortening patients' length of stay in the hospital or emergency department have widespread cost implications. CT scans can cost anywhere from hundreds of dollars to thousands of dollars.
Abbott isn't the only diagnostics company aiming to develop tests for traumatic brain injuries, however. Last year, BioMérieux received CE marking for a test to detect mild TBIs up to 12 hours after injury that uses both GFAP and UCH-L1 to rule out the presence of intracranial lesions, which could help cut out the need for a CT scan. BioMérieux partnered with Banyan Biomarkers to commercialize its TBI test in 2017 before Abbott nonexclusively licensed GFAP and UCH-L1.
Another company, BrainBox Solutions, has combined a panel of biomarkers with computerized neurological assessments to develop a test to help diagnose concussions. Medicortex Finland, meantime, is developing a lateral flow assay using an undisclosed glycan biomarker to detect concussions.