Why Testing May be Useful
Even though you may have good
rapport with your young patient, there may still be reasons why he or she is unwilling to
reveal substance abuse to you. As noted, denial that substance abuse is a
problem is common. In the early stages of involvement, the child is likely
to believe “I can handle it” and may resent adult intrusion. Later, when
use has become compulsive, lying is common to protect access to the drug. Young
people also fear the consequences if parents find out about their use and frequently
protect themselves by denying any involvement with alcohol and other drugs.
In one study of clinical diagnosis, based on emergency room visits, two-thirds
of the patients for whom the E.R. visit was drug abuse-related would have been
misdiagnosed without laboratory testing. An added complication of street
drugs is that the user may not be sure, or may have been misinformed,
about the drug he or she has taken.
What Testing Does
Urine toxicology screening provides an objective means of detecting use of a
wide range of abused substances at reasonable cost. It may help assess the
extent of drug involvement both on the basis of the drugs detected and by contrasting
the objective findings with the patient’s self report. Follow-up testing
after treatment is a useful means of verifying that use is probably not occurring.
While negative findings provide no absolute assurance that drugs are not being used (some
drugs cannot be readily detected or can only be detected for a brief period of after use),
they do establish that drug use has not occurred within the sensitivity of the testing
Substances that Can be Tested
The drugs for which urine is commonly screened include: amphetamines, cannabinoids,
cocaine, opiates and phencyclidine. Multiple screening is usually desirable since it
is more cost effective and since seriously involved youth may be using more than one drug.
More specialized and expensive techniques — such as gas liquid chromatography (GLC)
and high pressure liquid chromatography (HPLC) — are available when it is important to
confirm the presence of a drug by an alternative means, to very specifically
identify the exact drug that is being abused, or to measure more precisely the amount
Discussing the Findings with Patient and
Should the interview and/or the laboratory testing give evidence of drug use, the
nature and extent of the childs involvement must be explored. If other
behavioral signs of drug involvement are present, the test results provide objective
confirmation that drug abuse is a central problem.