The first simple saliva test has been developed by scientists.
It takes around five minutes and can be performed on the spot.
It identifies whether synthetic cannabinoids have been smoked and if so, at what concentration.
Spice, who may be unconscious, incoherent or experiencing psychosis.
Scientists say that the method of testing for such substances is a laboratory, with results taking days to come through.
Spice is a single substance and more than 100 subtly different man-made chemicals.
This means that a precautionary approach is often followed for such patients, which may not be the optimal course of treatment.
Those undergoing temporary psychosis may also be admitted to a psychiatric ward.
Dr Chris Pudney, at the University of Bath, described the results as "simple and very accurate" and easy to understand.
"My partner is a psychiatrist and he was telling me that they don't have a way to confirm when they suspect they use Spice, they just don't know for sure," said Dr Pudney.
"You can test it with a urine or blood sample.
"I started looking into chemistry and it's actually similar to something we have developed for detection of biological molecules.
"We decided on saliva because it seemed tractable and less invasive than some other options."
Dr. Pudney contacted colleagues at the University's Department of Pharmacy & Pharmacology, Department of Computer Science, to explore developing the device.
The NHS, drug charities and homeless charities.
To conduct the test, a saliva sample is taken from the patient and put into a small clear tube.
This tube is placed into the machine, which then uses light to scan for the "fingerprint" of a Spice compound.
Within five minutes, the result comes up on a screen.
Dr. Jenny Scott, of the Department of Pharmacy & Pharmacology, said: "Spice can be used to 'zombify' people, escaping them from the reality in which they find themselves, making them highly vulnerable.
"Two thirds of prison governors report concern about new psychoactive substances, including spice.
"Our collaborative research work with homeless people who use drugs has been found.
"Detection and confirmation of spice use early on when someone is found incoherent.
"Further down the line, we can foresee the pathway to be used as part of a care pathway.
It is hoped that medical professionals will be able to work within a year.
The prototype test is featured in the journal Analytical Chemistry.