PATCH THAT MIGHT KEEP TABS ON DRUG USE WILL BE TESTED IN PHILA.

The device would offer ``real-time'' data, rather than after-the-fact screening.

Sweating it out could take on new meaning for drug users caught by the
criminal justice system.

The federal government is getting ready to field test in Philadelphia a
black watch-sized patch that is being designed to send a signal if the
wearer takes drugs. It also has the potential to relay information to
authorities about the person's whereabouts, within 150 feet.

Considering that at least an estimated 50 percent of all defendants
nationally test positive for drugs, the patch could make it easier to
supervise convicted criminals when they return to their communities.

"It could open up a new and possibly foolproof method of monitoring
substance abuse," said Saralynn Borrowman, program manager for
investigative sciences at the National Institute of Justice, a research
agency for the U.S. Department of Justice.

Recognizing the close link between drug use and criminal activity, many
courts have already beefed up their efforts, requiring felons to enroll in
treatment programs and submit to drug tests. If they don't, they can face
jail time. Many courts also are monitoring drug users awaiting trial.

But such oversight can be costly, time-consuming and faulty, some experts
say. The sweat patch offers "real-time" data about drug use, said David A.
Kidwell, who is heading the research for the Naval Research Laboratory in
Washington. Other drug screens, such as hair analysis or urine tests, are
"always after the fact" and sometimes
"beatable," he said.

The patch is built into a band that can be worn on the wrist or the ankle.
In concept, the patch will work like this:

Say a person takes cocaine. The drug molecules are excreted in sweat. The
surface of the patch is coated with a specific antibody that interacts with
the cocaine. In the process, the cocaine molecules dislodge colored
particles on the patch and the released particles are detected by a
built-in sensor. The concept works somewhat like a home pregnancy test, in
which a color indicates a positive or negative result.

The patch then relays the information to a transmitter similar to a pager
- -- or potentially a small cellular or satellite phone -- worn by the
person being monitored. In turn, information is forwarded via wireless
e-mail to a computer, possibly several states away, identifying who the
user is and where he or she is.

Kidwell says versions of the patch could be developed for other drugs, such
as heroin and amphetamines.

In the initial tests to be done in Philadelphia, the patches are designed
to detect alcohol use. The aim is to see whether there are technological
bugs in the system. Kidwell said he hasn't yet decided how many people will
be involved in the testing, though the number will be small.

"What we have works," said Kidwell, whose tests so far have been confined
to the laboratory with fellow scientists. But, he said, he needs to find
out "whether it is easy to use."

Among the unknowns are whether the patch will be comfortable for the
wearer, if people can beat the system, and how easy it will be to service
the patches in the field. The patch is designed to monitor not only drug
status, but also skin temperature and whether the patch is in contact with
the skin, as a way of checking that it's being worn.

Kidwell has been working on the device for about three years under a grant
from the federal Office of National Drug Control Policy. For the field
tests, he plans to collaborate with the Institute for Addictive Disorders
at Allegheny University of the Health Sciences. Initially, Kidwell will
track alcohol use among volunteer patients from one or two Allegheny
programs. He also plans to have field tests in New Orleans in conjunction
with the city's district attorney's office.

He projected that it may take another two years before the drug-screening
patch is ready for wide-scale use.

Jerome Jaffe, who recently headed the federal Center for Substance Abuse
Treatment, said the patch might be better at deterring drug use than
methods now in use. The key may be the immediacy of getting caught.

"People have found that the closer you make the consequences and the
behavior, the more likely it is to influence behavior," said Jaffe, now a
psychiatry professor at the University of Maryland.

But for some, the technology is troubling.

"It is like a scarlet letter," said Caroline Cooper, a former public
defender, who is director of the drug court clearinghouse at American
University. She questions whether such constant monitoring would conflict
with the constitutional protection against unreasonable searches and
seizures.

"Unless there is some egregious situation that warrants the intrusion,
wearing a patch 24 hours a day would bother me," Cooper said.