Results of limited versus comprehensive toxicology screening in a university medical center.

Both comprehensive toxicology screening (COM) and limited toxicology screening (LIM) were performed on the same urine in 1,734 consecutive cases over a 6-month period at a university medical center. About half of the screens originated from inpatient services and half from outpatient services (mostly emergency department). In 71 % of the cases, there was agreement between the results of LIM and COM, with 47% of cases being negative. For 500 screens (accounting for 655 individual discrepant findings), at least one discrepancy was noted between LIM and COM. Of these, 399 cases demonstrated at least one finding with COM, but not with LIM ("false-negative" LIM). Topical anesthetics (including cocaine and cocaethylene), antiepileptics, and sympathomimetic amines accounted for 65% of findings. In contrast, 147 cases showed a finding with LIM, but not with COM ("false-positive" LIM), mostly amphetamines. In certain specified clinical circumstances, LIM may be a more cost effective and efficient approach than COM.