Many labs routinely test for contaminants because of adulteration. Urinalysis cannot measure impairment or other behavioural effects of drugs. . Drug testing programmes are very expensive. Urinalysis cannot determine precisely when the drug was used nor can it identify the quantity of the drug ingested. To be even reasonably sure of continuing drug free status, frequent re-testing would be needed this is very intrusive and very expensive.
Drug testing is extremely intrusive of the right to privacy.
Random drug testing programmes have an extremely negative impact on morale. Lack of procedural safeguards with respect to urinalysis. A wide variety of drugs, including alcohol and tobacco, are available in prisons. It is also reasonable to predict that a random drug testing programme will result in a decrease of those drugs that it is most likely to detect. In short, then, the programme is likely to reduce the use of marijuana and increase the use of alcohol and certain other drugs.