Pathologist keeps track of
economic implications of laboratory tests
BY KRISTIN WEIDENBACH
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
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