As Drug Testing Kits UK, is all too aware: "Drug misuse in the workplace can lead to lower productivity, high absenteeism rates, and a higher number of workplace-related accidents and injuries. Individuals who suffer from drug addiction may call in sick regularly to recover from hangovers or to deal with the crash that follows cocaine or methamphetamine use. Employees may also take longer lunch breaks or arrive to work late to spend that time buying or using drugs" 
So What Can Companies Do to Negate Illegal Drug Use?
Research shows that watching employees' behaviour and productivity is not a sufficient means to establish which members of staff abuse drugs. For example, someone may have continual poor productivity due to a chronic illness, whereas someone healthy who abuses illicit drugs, may only falter when they are transitioning through the aftermath of the negative effects of the substance they have taken. - A common case in point is after a weekend fuelled by smoking marijuana.
In addition to the aforementioned, the list of signs of illicit drug use is very long, and someone's odd behaviour in the workplace does not necessarily mean that they are partaking.
Moreover, studies indicate that there is not a 'typical' type of drug abuser. Indeed, using and being under the influence of illegal drugs at work, is prevalent among employees from all social economic groups and age categories. To that end, the Health Science Advisor at Drug Testing Kits UK, strongly recommends that all companies and organisations conduct periodic announced and unannounced on-site drug testing. - Testing which incorporates both popular illegal drugs, and abused prescription drugs. The latter of which is also a problem in the UK workforce.
Of note, these on-site drug tests can be conducted by an assigned employee (who has studied the easy-to-follow instructions, and carried out a few practice runs). Drug Testing Kits UK's CE certified, UK-approved, non-invasive, cutting-edge, highly accurate, rapid, (the results are visible within a couple of minutes), '7 Panel Oral Fluid (Saliva) Multi Drug & Alcohol Test Kit,' is hugely popular with many thousands of companies across the length and breath of the UK and Southern Ireland. And they have the bonus of testing for alcohol as well as the 6 commonly used drugs. The drugs which are screened for in this highly recommended saliva test include:
Ketamine, as well as
Drug & alcohol metabolites (by-products of the body breaking down (metabolising) drugs or alcoholic beverages (wine, spirits and beer), into different substances. The process of metabolism is certain and predictable, and everyone metabolises drugs in the same manner)
"When one of your employees has a problem with alcohol or drugs, it can impact the whole work group. Problems can appear in areas such as meeting deadlines, team communication and morale, accidents, absenteeism and more. The adverse economic impact of employee drug use on employers is well documented. Moreover, co-workers are asked to pick up the slack when an impaired colleague is absent. They may end up taking on extra assignments and working longer hours. This can lead to long-term resentment and increased stress. Also, the safety of co-workers can be at risk if a drug user is under the influence" [1, 2]
What's the Level of Substance Abuse in the Workplace?
Did you know that addiction in the workplace loses companies countless hundreds of millions of pounds each and every year? And that:
Lost profits are linked to high turnover rates, low productivity, high absenteeism, and workplace theft
Of the 70% of staff who continue to work while being addicted: over 42% report experiencing decreased work productivity
Alcohol is connected to 16% of emergency hospital visits for work-linked injuries, and more than 10% fatalities within the workplace
Approximately 63% of individuals who report misusing prescription opioids are employed
Around 43% of deaths via drug overdose (that occur at work), involve staff who work in the: transportation, construction, healthcare, warehousing, and social service industries
Staff who are addicted: "miss an average of 14.8 workdays a year, while those who suffer specifically from opioid addiction miss an average of 29 days a year" 
Health Issues and Frequent Illnesses
As Drug Testing Kits UK's educational blogs often point out to employees: "Drug misuse and addiction will often trigger or worsen many health problems. Persistent flu-like symptoms, dental issues, fluctuations in weight, and gastrointestinal issues (e.g., upset stomach, nausea, diarrhea) are some of the many common health problems experienced by those who misuse drugs and alcohol. Substance misuse also increases the risk of mental health disorders, including depression, anxiety, and schizophrenia. Employees who appear to be feeling sick at work all the time may be using drugs, especially if they are frequently calling in sick 
Our Drug Testing Kit UK's professional advisors have seen that judging by the experiences of some companies and organisations; many of these situations have been allowed to carry on unfettered, and in some cases, for years on end. - Yet this has simply been due to that fact they did not get around to decisive action. - That is to say, they did not create a workable strategy which added mandatory regular drug and alcohol testing in the workplace, to employees' work contracts. - So as a result, they did not conduct any on-site drug and alcohol testing.
One reason for this, was the expense of bringing in a medic, and having the drug and alcohol tests send off to a lab, which charges a great deal of money. - But fortunately, both these practices have now changed. And Drug Testing Kits UK is proud to be part of the revolution that had empowered employers to conduct workplace drug testing. All they have to do is to assign a responsible employee to conduct the simple to use, highly accurate British approved saliva tests. - CE certified tests which show the results within a couple of minutes. So thee is no need to hire a medic, or pay expensive labs.
So in summary, companies and organisations no longer have to take pot shot guesses about their employees' behaviour, they can simply use Drug testing Kit UK's low cost state-of-the-art rapid lateral flow saliva test which provides qualitative detection of multiple drugs and drug metabolites, while simultaneously testing for alcohol.