Drug tests for many of the most popular illegal drugs are now widely available for home use in South Africa, enabling parents, for example, to check if their children are taking drugs.
But drug research and counselling organisations have warned against using the tests
in isolation.
The simple urine tests are sold in pharmacies and range in price from R10 to more than R60 and can test for many of the addictive drugs including the extremely popular tik (methamphetamine), dagga, hashish, cocaine, heroin, opium and ecstacy.
They can also be used for over-the-counter medicines such as codeine and benzodiazepines such as Valium which also have addictive elements.
Tests for specific drug groups as well as tests that check for a broader selection of drugs are also on sale.
Tertius Cronje, Director of Corporate Services for the South African National Centre on Alcoholism and Drug Dependency based in Cape Town, said that home drug testing should be approached with caution as it could be abused and could do more harm than good.
"One problem is that parents are very subjectively involved in this process and their response may come across as forceful to the child."
He said that an important point to consider was that using a drug test would not restore harmony in the household and could result in damage than good, regardless of the result.
A major danger of these home tests, Cronje said, was that if the parents did not understand the tests and what the results meant, they could project other things onto the results.
"All that one can infer from a positive drug test is that the person has used the drug some time within a certain time frame, nothing more. It doesn't say whether the person is an addict or a once-off user which parents may ascribe to the results even though it isn't there."
"All that the home use provides is an opportunity for parents to show to their children that they are using drugs. It cannot help them to stop, which is the ultimate goal."
He stressed that the tests were not foolproof and many children scanned the internet and knew a myriad ways to avoid showing up positive on drug tests which then provided parents with a false sense of security.
Cronje conceded that mature use of testing could allow parents to define a "bottom-line" for their children and make them aware of the realities of drug addiction and abuse.
Andreas Pluddemann, a senior researcher at the Alcohol and Drug Abuse Research Unit of the Medical Research Council said the MRC was very confident about the reliability of the over-the-counter tests.
The technology of the test has been available for more than six years and more tests were becoming available in SA.
"It does reflect a problem in society when home tests are available but that is the reality."
He advised parents to approach the situation with caution and to contact a counsellor or drug centre for advice on the tests and, more importantly, what the results meant.
He explained that urine tests were the most common tests available but stressed that they did not provide any other data such as the amount of drugs in the system and how regularly it was used.
They found in their research using the broad spectrum tests and comparing them with other drug-specific hand-held tests for cannabis and a laboratory test for Mandrax, that there was a high correlation of results - "which is why we are so confident about these tests."
A local distributor of one of the drug test kits said that there has been an increase in use of the tests, which bore testament to the growing awareness of the problem.
Jaco Henning of a company that distributes the drug tests, said that the most popular test was the one that tests for the "big five" drugs and covers a broad spectrum of various drugs available to users.
The big five are amphetamine, methamphetamine, dagga, cocaine and the opiates (opium and morphine).
"Most people start with dagga which is the gateway drug, but then eventually move on to other drugs and it is seldom that anyone uses a single drug."
He said that there has been a growing increase in acceptance of the tests in social circles which has contributed to its growing sales.