A blood test aimed at guiding management of patients suspected of having concussion won FDA approval on Wednesday, the agency said.

The test, which measures levels of two proteins in blood, does not by itself provide a firm yes/no as to whether a patient has suffered a brain injury. Rather, it’s an indicator of the likelihood that a CT scan will show intracranial lesions, and hence may be valuable in deciding whether CT scans are indicated.

Currently, it’s routine to order a CT scan for all patients with suspected closed head injuries, the FDA noted, but most scans do not show detectable lesions. The blood test is thus expected to cut down on these unhelpful scans and the associated radiation exposure.

Developed by Banyan Biomarkers, the Brain Trauma Indicator test is a quantitative assay for ubiquitin carboxy-terminal hydrolase L1 and glial fibrillary acidic protein, which are released into the blood following neural injury. The test should be performed within 12 hours of injury; results are available in 3-4 hours, the FDA said.

Trial data involving nearly 2,000 individuals with with suspected concussion or mild traumatic brain injury (mTBI) showed that the test was 97.5% accurate in identifying those with visible lesions on CT scans, and 99.6% accurate in predicting those who did not show such lesions.

“These findings indicate that the test can reliably predict the absence of intracranial lesions and that healthcare 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 agency said.