a blood test for concussions?
The New York Times recently published an article about a new blood test for concussions. This is an exciting new step in concussion care. However, there are still many unknowns before it becomes useful to the everyday sports medicine physician. Here is what we know and don’t know about this test so far, plus what to look for next.
When evaluating an athlete with a head injury, there are two things to consider
- Is this a concussion? Athletes with a concussion may show symptoms immediately, but it can take up to 72 hours. Making a diagnosis of concussion on the sidelines can be difficult. It is easier after a few days, once you have time to see if the athlete develops symptoms. CT scans have normal results and are not recommended as standard care. Contrary to popular belief, these athletes do not need to go to the emergency department. They can be managed at home with rest, then follow-up in clinic.
- Could there be other injuries that are worse than a concussion? This includes things like skull fractures or life-threatening bleeding in the brain. Athletes will show signs within minutes to hours. Worrisome signs include loss of consciousness, repeated episodes of vomiting, inability to stand upright, or difficulty waking up. These injuries need a trip to the emergency department for a CT scan. Most are normal, and the athlete just has a severe concussion. However, it takes a visit to the emergency department, a large dose of radiation to the head, and sometimes overnight hospital observation before this can be certain.
what we know:
- The test was designed to help those on the field decide if a known head injury needed a trip to the emergency department for more severe injury.
- The test looks for proteins that the brain releases into the blood after an injury
- The test should be performed within 12 hours of injury to be reliable.
- The test is very good at predicting which head injuries will have abnormal findings on CT scan, indicating injuries more severe than concussion. This will help doctors figure out which injured athletes should go to the ER for a likely abnormal CT. It will prevent those with an isolated concussion from unnecessary CT scans and radiation.
what we don't know:
- We don’t know how accurate the test is at diagnosing concussions if they are not associated with more serious injuries. This includes the vast majority of head injuries from sports.
- We don’t know how long it takes for the level to rise. Will we be able to diagnose a concussion 2 minutes after the injury, when the coach is eager to get a player back out on the field?
- We don’t know how long it takes for these levels to get back to normal after an injury. A normal level 5 days after injury does not guarantee there was not a concussion.
- We don’t know if children will have the same reliability with the test. So far, it is only proven in adults.
- This test does not address the problem of repeated hits over time. Individually these may not cause symptoms, but some research shows that these also contribute to long-term effects of repeated concussions.
This is a promising test to screen which injured athletes need a CT for potentially life-threatening head injuries. There is not enough known about it to use in the day-to-day diagnosis and management of concussions in youth sports. It is a huge step in the right direction and I am looking forward to further research in this area.
Baseline concussion testing
While we are still waiting to learn more about blood testing for concussions, one of the best ways we have today for diagnosing a concussion is by having a baseline test done ahead of tiime. This service is free to families and can be done for kids 10 and older. Dayton Children’s uses a concussion testing system called Neurocognitive Sports Computerized Cognitive Assessment Tool (CCAT) to help measure the cognitive function of child and teen athletes after suspected concussions or traumatic brain injuries (TBI).
Concussion testing is best done when athletes establish a baseline using the CCAT's four simple tasks. Repeating the same tasks after injury identifies any cognitive changes from the baseline test performance. Concussion testing is just one of many tools our doctors use for athletes with concussions.