How to trim your lab tab: Use an expert to screen

Requests for sputum and culture exams cut by 40%

When it comes to diagnosing and treating tuberculosis, bringing in the specialists isn’t just a way to save money in the long run; sometimes it pays off right away, according to a study at New York University Medical Center and Bellevue Chest Service. 1

Consider the Bellevue facility in New York City, for example, where every year, more than 10,000 sputum AFB smear and culture examinations are performed. At up to $150 apiece — that’s counting between $30 and $50 for the smear and $100 for the culture — the total tab for the exams is staggering. And just as elsewhere, very few of the samples examined turn out to be positive for M. tuberculosis.

There appeared to be a need for a screening procedure that could trim back the volume of the unnecessary tests, without eliminating any of the tests that turned up positive results. Those were the thoughts that came to Ruth Divinigracia, MD, a fellow in the Division of Pulmonary and Critical Care Medicine at Bellevue. In pursuit of such a procedure, Divinagracia arranged for two pulmonologists on staff at Bellevue to conduct a prospective review of one month’s worth of requests for sputums and cultures.

Of 131 patients eligible for the study, it was possible to locate chest X-rays for 97 patients. The pulmonologists looked at the X-rays, along with case histories and results of physical examinations, for each of the patients. Then their opinions as to whether the lab work was actually warranted were compared with the results of the lab work.

Divinagracia’s preliminary analysis of the results (a more thorough analysis is presently under way) has been encouraging. All six of the patients whose lab reports were positive for MTB were caught by both pulmonologists, who agreed that laboratory examination was warranted in all of those instances. (In addition, one patient whose chest X-ray both experts pronounced to be of such poor quality that it couldn’t be interpreted also eventually turned out to have been positive.)

Two experts agreed 84% of the time

The two experts also agreed that about the same number of patients needed to have sputum and culture examinations, with one putting the total at 51 patients, and the other at 52. The two sets of patients correlated with each other only 84.5% of the time (that is, 84.5% of the time, both experts said "yes" to a request, or they both said "no"). But in the cases of the 14 or 15 patients about whom they did not agree, none turned out to be positive for M. tuberculosis, Divinagracia adds.

Divinagracia concludes that if the chest service had taken the pulmonologists’ advice, the facility would have cut back the volume of tests (and attendant costs) by about 40% — without missing any positive results. The same system probably could be implemented at any big hospital, especially "any academic institution with an active pulmonary service," she adds. In such facilities, the specialists are "paid regardless of whether you use them. Adding this onto their duties won’t add much to the work of the department, but it will cut costs," she says. By comparison, for a smaller institution to call in specialists for consultation every time smear and culture are ordered wouldn’t be cost-effective.

The study seems to show that implementing such a system wouldn’t require facilities to use two experts, either, she says. "Since neither specialist missed any [of the positives], one would probably be fine," she says.

In the course of the study, Divinagracia discovered that a large proportion of the requests for sputum and culture at Bellevue come from psychiatrists. The reason, it turns out, is that state law requires PPD skin testing on all candidates for admission to state psychiatric units. Yet psychiatrists may lack the clinical experience needed to evaluate patients whose skin tests turn out positive and often resolve the question by ordering lab tests.

Studies like hers do more than just offer a way to trim costs, Divinagracia adds; they also supply support for the notion of using specialists. "In this day of HMOs and cost-cutting, what this study is saying is that we pulmonologists are not redundant," she says with a laugh. "We do in fact have a role."

Other studies tend to support the notion that using experts can often shave costs, Divinagracia points out. In particular, when specialists are used to oversee treatment for asthma sufferers, savings are enormous because patients who don’t suffer frequent asthma attacks are spared visits to emergency rooms.


1. Divinagracia R, Bonk S, Rom WN, et al. Screening by specialists to reduce unnecessary sputum AFB smear and culture examination (abstract). Am J of Resp and Crit Care. 1997; 15:A555.