What are they looking for in a urine drug test.  What does a urine drug test reveal?

Hi,

Depends on the drug, but almost all narcotic, hallucinogenic and
herbal drug series appear in urine after consumption.

The usual panel includes:

Amphetamines
Opiates
Benzodiazapenes
Cocaine
Cannabanoids
Barbituates
Methadone
TCA
Paracetamol
Salicylate
Chloral Hydrate

This list can be smaller or larger depending on what the hospital
tests as per standard regulations. The urine drug test of these
substances will reveal the levels/concentrations of the drugs
mentioned.

Hope this helps :)
Baz

In the urine drug test, they look for either active drug which is
secreted as such, or an active metabolite of the drugs. Urine drug
tests are carried out with chemical reagents for perticular drug/drug
metabolites. There are specific changes in the solution (like
appearance of specific color or precipitate etc) whtch is specific for
the perticular drug/drug metabolite.
  Drugs underwent metabolization in the liver and specific metabolites
are produced which in turn are secreted by body through urine. These
metabolites are tested with specific reagents, if reaction is
positive, this confirms that the person has taken drug.