The unproven utility of the preoperative urinalysis: economic evaluation.

The clinical effectiveness of the preoperative urinalysis is unproven, yet it is routinely obtained before surgery. To determine if the routine urinalysis might be economically beneficial, we evaluated its cost-effectiveness and cost-benefit. In the setting of elective clean-wound, non-prosthetic knee procedures, we estimated that: (1) nearly U.S. $7,000,000 is spent annually on preoperative urinalyses and associated costs; (2) given the best estimate of the increase in risk of wound infection attributable to urinary tract infection, 4.58 wound infections may be prevented annually, at a cost of $1,500,000 per wound infection prevented; (3) the cost of treating additional cases of wound infection, given no preoperative urinalysis, is approximately five hundred-fold less than the cost of screening with routine urinalyses. We conclude that the routine preoperative urinalysis is clinically and economically unsound before clean-wound, non-prosthetic knee surgery and probably before other types of clean-wound surgery. For this relatively inexpensive test, aggregate costs are disproportionately high and appear to outweight clinical benefits.