A new study from the Swedish medical university Karolinska Institutet presents a new technique that makes drug testing possible through exhaled（呼气，发散） air for the first time. By examining people who had received emergency care for an amphetamine（苯丙胺） overdose（服药过量） , the researchers found that in all cases there were traces of amphetamine and metamphetamine in the exhaled breath. "Traditionally, drugs tests have been carried out using urine and blood samples," says Professor Olof Beck, who led the study. "In recent years we've been trying to find simpler alternatives using saliva（唾液） , which, unfortunately, has proved difficult. Our results open the way for a new kind of drugs test, which is simple and safe to conduct and that requires no integrity-violating monitoring or medical staff."

Drug abuse is a huge social problem and drugs tests are used widely and comprehensively by the healthcare and social services, the legal system, at workplaces and schools. Reliable drugs tests are important for making correct diagnoses and for keeping tabs on（监视，密切注意） drug users to ensure that they are following their prescribed treatment. Alcohol use can easily be checked in a breathalyser（呼吸测醉器） , and the technology is available for conducting measurements in a way that does not violate a person's integrity. Measurements of other substances in the exhaled breath are also available for diagnosing diseases such as cancer, asthma（哮喘） and diabetes（糖尿病） .

In this present study, which is published in the latest issue of the Journal of Analytical Toxicology, scientists at Karolinska Institutet have developed a new and unique method for collecting narcotic（麻醉药） substances from the exhaled breath. This they did by asking subjects to breathe into a specially designed mask for ten minutes, whereupon（因此，于是） the exhaled air was collected and passed through a filter, which trapped the narcotic substances. These filters were then analysed using combined liquid chromatography（液相色谱法） and tandem mass-spectrometry, techniques that are highly sensitive and reliable.

The researchers took samples from 12 patients who had been admitted into emergency care with toxic symptoms after having taken amphetamines（安非他命） . The samples were taken after the effects of the drug had worn off and with the permission of the regional ethical review board in Stockholm. The ingestion（摄取，咽下） of the drug was confirmed in the patient group through urine and blood samples. In all cases, the researchers were able to ascertain（确定，查明） the presence of amphetamine and metamphetamine (a narcotics-classed central-stimulating substance similar to amphetamine) in the exhaled breath as well. The measured excretion rate was between 0.2 and 139 pg/min, which is very low compared to the blood and urine. No amphetamine or metamphetamine were detected in samples from healthy controls.

"The results are convincing and very promising," says Professor Beck. "The study is the first to report the possibility of measuring drugs in the exhaled breath, and represents a unique, unexpected finding. We now have to move on to other drugs that are of interest for this type of breath test, and to develop the sampling and analysis methods. An instrument like a breathalyser for drugs would be the optimal solution for the efficient control of drug use by motorists（驾车旅行的人） , for example."