It would seem that the ordering of testing of sputum for AFB at Iowa at that time period was excessive, especially given that almost half of the control patients had only one sputum specimen sent. Despite this apparent interest in diagnosing tuberculosis, only 42 percent of tuberculosis patients were isolated on admission. One wonders if physicians are lulled into complacency about tuberculosis since so many of the positive AFB smears proved to be NTM. This increase in NTM compared with tuberculosis has been reported elsewhere (21, 69) as well.

Although the authors did not calculate this, using their estimate of 30 contacts per case, the 14 nonisolated tuberculosis patients would have exposed 420 health care workers at a cost of 105 nurse epidemiologist hours ($2,100 at the $20/hour they estimated), plus an additional $2,520 to $4,620 for PPD testing.

Kerr and Savage (70) calculated the potential cost of exposure to a single nonisolated patient in a postanesthesia care unit (PACU). Based on traffic in the PACU and typical recovery times, they estimated that a patient with tuberculosis would expose 24 other patients, 10 PACU staff, 38 operating room staff, and 9 ancillary staff (total 81). Cost and time estimates were from Brown et al. (70) and Scott et al. (67). Their results follow: