It can identify damaged cell proteins in brain tissue samples, which are early warning signs, or biomarkers, of the illness.
ALS, sometimes referred to as motor neurone disease, is an incurable neurological and brain disorder that progressively worsens muscle weakness.
It affects roughly 5,000 persons in the UK and can drastically reduce life expectancy.
Experts from the University of Aberdeen have developed a new test called TDP-43 aptamer.
A build-up of specific proteins in the brain causes motor neurones, the cells that deliver messages to the muscles, to gradually stop working, which is the cause of motor neuron disease (MND).
Early warning indicators include slurred speech, a weak grip, weakness in the leg or ankle, weight loss, and spasms and twitches in the muscles. Symptoms can develop gradually.
The new test may be able to detect MND symptoms earlier and with greater sensitivity.