There has been a significant increase in the number of Irish companies drug testing their employees.
A Northern Irish lab has said its traditional customer base of US or multi-national companies has evolved, with a number of indigenous firms now seeking their assistance.
Scientists examine blood, saliva and urine samples given by workers when they are testing for traces of drugs or alcohol.
Gary McCutchinsons from Randox Laboratories said employers are acting on their responsibility to provide a safe working environment. He also explained why multiple samples are needed.
Each different sample type has a different detection window," he explained. "So, for example … saliva only has a detection window of a couple of days - but the benefit … is a drug is detectable almost instantaneously after ingestion."
"A drug will be detectable in urine for up to five days, and in some instances – such as cannabis – for much longer."