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Stanford Report, May 24, 2000

Pathologist keeps track of economic implications of laboratory tests  


Cost containment is an issue that Stanford grapples with, as do most hospitals across the nation. Individual departments work to shave unnecessary expenses without impinging on patient care. One example is the clinical microbiology and virology laboratory where director Ellen Jo Baron, PhD, associate professor of pathology, continually monitors the palette of diagnostic tests to ensure that patients have access to the best and most cost-effective tests.

In a talk titled "Economic Ramifications of Laboratory Tests," Baron summarized recent changes and advances in her laboratory. She spoke at the 100th annual meeting of the American Society of Microbiology, which took place in Los Angeles, May 21 through 25.

Stanford's microbiology/virology laboratory provides more than 300 different tests for bacterial, fungal and viral infections. But the array of tests the lab offers changes according to the season and as new tests become available. "We do our own internal validations in the lab and we tell [the physicians] what tests we're going to offer," said Baron. "We try to let them know when we're going to make changes and why. The infectious diseases clinicians help us to implement and publicize changes to the rest of the physicians."

For example, during the winter months, when influenza and respiratory viruses are on the rampage, the laboratory offers three tests, each with different advantages and disadvantages, to diagnose respiratory syncytial virus (RSV). At other times of the year, offering two tests is usually sufficient.

During the RSV season, typically from October through April, staff in the laboratory record all cases that they detect and chart the number of cases over time to determine when the season has ended and the risk of new infections is low. Physicians are particularly interested in pinpointing the fall in number of RSV cases, which causes a mild common cold-like syndrome in adults but more serious lower respiratory tract illnesses like pneumonia and bronchitis in children. The virus is extremely contagious and can lead to serious illness in children with weakened immune systems, or in infants with damaged or under-developed lungs.

"This is an important marker in our hospital because a certain drug -- synagis -- is given to all immunocompromised kids. [The doctors] will stop giving it when RSV season is over, so they watch my chart very carefully," said Baron. Synagis costs $500 to $1,500 per patient per monthly dose. This year, the RSV season finished at the end of March, she said; and the flu season, which peaked at Christmastime, finished at the end of January. According to Baron, the Stanford lab is one of the few places that performs viral culture tests, and so the State of California looks to their RSV monitoring and results are also sent to physicians at the Palo Alto Medical Foundation.

Baron has also reviewed how frequently physicians at the Medical Center order blood cultures. Sepsis, or infection of the blood, is diagnosed by incubating a sample of blood in the lab so any microorganisms in the sample can grow and be detected. Sepsis, which usually arises from microorganisms spreading from the gastrointestinal tract or skin into nearby tissues, is now a contributing factor in more than 100,000 deaths per year in the United States. Approximately two-thirds of cases occur in patients who are hospitalized for other illnesses.

For patients suspected of having or at risk of having sepsis, Baron says that physicians should draw sufficient samples so that the condition can be diagnosed before the concentration of bacteria circulating in the blood becomes dangerously high. However, blood should not be drawn needlessly. She compared the number of blood cultures the Stanford lab received per patient day with figures from four other hospitals. "Stanford sits smack in the middle between overuse and underutilization of blood cultures. It makes me feel very good about how Stanford physicians are using our blood culture system," she said.

Another topic Baron discussed in her talk is a study that led the lab to change its protocol for diagnosis of endocarditis -- a potentially fatal infection of a heart valve. The protocol the lab used to implement was designed to capture the fastidious, difficult-to-cultivate bacteria that cause the condition. Samples of blood were grown repeatedly, for several weeks on many different types of media and under different conditions, such as with or without oxygen. It took 52 days to get the final result. It was a "very expensive, labor-intensive, long, drawn-out process," said Baron. But many labs now use an automated blood culture system to find the organisms that cause the infection.

Working with fourth-year medical student John Scott, Baron surveyed protocols at other hospitals that, like Stanford, use special practices to cultivate these organisms. They also reviewed the results at Stanford from 1995 through 1997. Over that three-year period they found that an average of 72 cases were subjected to the specially designed endocarditis protocol at a cost of $11,180 per year. Fifteen organisms were detected that were not found in routine testing, and of these, only three were considered clinically significant, according to Baron. In those instances, the patient's clinical symptoms would have prompted the lab to perform alternative tests that also would have detected the organism. So Baron halted the cumbersome testing process. The laboratory's standard blood culture protocol now suffices. In instances when the physician suspects a fastidious organism likely to evade detection, the laboratory consults with an infectious disease physician and initiates a special blood culture protocol.

Baron gave a second talk at the Los Angeles meeting in conjunction with an award she is receiving -- the BioMerieux Sonnenwirth Award for Leadership in Clinical Microbiology. SR