As the Rugby World Cup semi-finalists line up for a spot in the coveted final, a team of Kiwi scientists and clinicians are developing the first on-the-spot test to diagnose sports-related concussion.
More than 7000 New Zealanders suffer head injuries playing sport each year and experts believe this new test will capture many more that go undiagnosed.
How ever you look at it, a knock to the head doesn't look good.
Rugby's Ben Smith, Ryan Crotty and Richie McCaw know the perils of concussion all too well.
But getting an accurate and reliable handle on it remains problematic.
ESR scientist Dr Rachel Fleming says currently there is no way of diagnosing concussion.
"It relies on people's impairments, whether they've hit their head or headache, feel nausea or they've been knocked out," she said.
Now ESR scientists are exploring a way to quickly and accurately diagnose concussion by simply testing a person's saliva.
What they're looking at is the RNA. Closely linked to our DNA, it's a unique marker in every human cell.
"Our theory is that if you have a concussion your brain's been injured, your brain cells would have been injured and possibly they'll have lysed - so open up so all the contents including the RNA will then come out and cross through the blood brain barrier.
"So then we're hoping we can detect that in body fluids and blood," Dr Fleming said.
Former Auckland Blues doctor and leading sports physician Stephen Kara says it would be a major step forward.
"We don't have a gold standard test and we would love to have a gold standard test," said Dr Kara of the Axis sports concussion clinic.
Right now, initial sideline tests for concussion involve asking the player some questions to test their cognitive function, some memory tests and some basic balance tests, much of it is subjective.
"We're hoping in the future to be able to collect the sample and within a few minutes be able to see yes they've got a concussion," Dr Fleming said.
Dr Kara said: "This would give us a lot more objectivity if we found a test that was reliable."
Such a test would have helped tennis player Christina Piet.
"I took a really hard ball to the temple," she said.
She didn't realise she had concussion for days.
"After four or five days my body just let me know it wasn't right and I basically shut down physically and mentally."
She's now well on the mend.
ESR's Rachel Fleming says a more effective diagnosis will mean fewer people go untreated.
She expects to develop her sideline test within a couple of years.