Using pitchside saliva tests to diagnose concussion is a step closer after a "game-changing" trial among male elite rugby union players.

Using microscopic DNA markers in saliva, they made a test that predicted an HIA result with 94% accuracy.

However, the test cannot yet be used on women because of a lack of data.

The study's chief investigator, Prof Antonio Belli, said that presented an "opportunity to bang the drum for more of this research to be done in groups not traditionally included".

Prof Belli described the study's findings as "game-changing", adding: "When I see on TV a player is taken off for the medical saliva test, it will be a major achievement."

Though a laboratory test could be in use within the next few months for elite players, a pitchside test that delivers instant results could be several years away.

The new technology could also be used beyond sport, potentially in general medicine and the military.

What are the study's findings?

The three-year study was carried out by the University of Birmingham, in collaboration with the Rugby Football Union (RFU), Premiership Rugby and Marker Diagnostics, a company which specialises in biomarkers

Dr Simon Kemp, the RFU's medical services director, described the findings as "incredibly exciting" and said the potential for the test was "far bigger than rugby".

He told BBC Sport: "It sits across all head injury, but within a rugby setting we know you can get a change in biomarkers very quickly so you could have a test in a medical room at a game and certainly that could be fed back the next day in the elite game."

Belli said the study was a "breakthrough" and he had "never really seen something so exciting" in a field of work that has previously relied on blood samples.

He explained: "Blood is much more difficult to work with and doesn't really work for a pitchside test or for children.

"Now you have something that is non-invasive, quite easy to get, objective and accurate at the same time."

Further stages of the study will look at brain injury in retired players in contact sports, with Prof Belli confident they will have "something exciting soon".

The RFU, World Rugby and the Welsh Rugby Union are facing a lawsuit from retired players suffering with early on-set dementia.

Could it be used in football?

The Premier League is conducting separate studies into the early signs of dementia and is in talks about working with the University of Birmingham team around three-minute concussion substitution rules.

The saliva test is laboratory-based, but the speed of development in testing following the Covid-19 outbreak could see that evolve quickly.

Prof Belli said concussion biomarkers are present in saliva "within minutes" after an injury, that a three-minute test was "theoretically possible", and that it was intended the study would be expanded into these areas in the next few years.

How about outside sport?

Prof Belli highlighted the saliva test's potential for use in military conflict, as well as it being "quite significant" for the National Health Service.

He said between a third and a half of brain injuries in road traffic accidents can go undiagnosed, adding: "To be able to make that diagnosis from a simple test could potentially change the outcome for that patient."

And the test's use may extend beyond concussion.

"It's fast becoming of interest as a possible target for liquid biopsies for cancer and heart attack, and other conditions that would normally require a blood test," said Prof Belli.

"If you can get the data from saliva you can get it at a GP and test children, it opens up a number of avenues."

What about concussion in women?

Prof Belli believes women suffer symptoms that are "more severe and more prolonged" than men, and that "to say this test would work in women would be wrong".

Dr Kemp said: "In the women's international game we run the HIA, we don't in the women's domestic game. There are very real aspirations for that to change very quickly and that would be a personal objective of mine to help that happen."

The RFU hopes to collect data in the "next phase" of the women's Premier 15s, and had wanted to do likewise at the Rugby World Cup, which has been postponed because of Covid-19.

What happens next?

The current findings will be presented to the World Rugby Symposium later this month with the hope two further global competitions will join the study to gather data, refine the algorithm, and provide independent verification of the findings.