Labs obliged to perform properly ordered tests
brain natriuretic peptide (BNP)
testing in our lab. When the manufacturer trained us, we were told that
the method we use is for a diagnostic tool only. Some of our physicians,
however, have been ordering daily BNPs on some of our patients,
obviously using the test to monitor the patient. I have asked the
chemistry technical supervisor about this and was told that if the
physicians order this test, we have to run it. Does this bring in a
liability issue if we allow the physicians to use a test in an
A BNP rapidly entered the literature of laboratory medicine as a reliable tool for
screening for congestive heart failure (CHF). Studies in both Europe and
America demonstrated its utility in establishing the diagnosis of CHF,
providing quick and accurate triage for patients with respiratory
distress, and also in evaluating the severity of the process involved.
BNP is attractive because it is a fast and available point-of-care test.
Its appeal to physicians has become obvious to laboratories that have
instituted BNP testing as part of their testing panel.
Your question concerning use of BNP poses some
interesting problems. Important with any newly introduced test is that
the laboratory establish sensitivity and utility of the method and
educate the medical staff accordingly. Although the initial impetus for
BNP testing was to facilitate the diagnosis of CHF, subsequent use and
studies have indicated that BNP levels may be used in conjunction with
clinical observations to provide an assessment of the severity of
illness as a means for following patients. If you have indications that
your medical staff is using the test in this manner, the lab should take
steps to determine whether or not the test is sufficiently
discriminating to provide physicians with the information they need.
Also ensure that the medical staff is well versed in
how to use the test. This probably means an inquiry to the manufacturer,
a research of the literature regarding the specific methodology your lab
is using, and an evaluation by the appropriate medical staff committee.
Your concern provides a perfect opportunity to offer the medical staff
an update on the nature of BNP testing, perhaps in the form of a
newsletter, including manufacturer recommendations and test limits.
Your supervisor is correct: Except in extraordinary
circumstances, the lab is obligated to perform any properly ordered test
that is within its ability to perform. The ultimate issue here is not so
much that the manufacturer markets the test as a diagnostic tool, but
whether or not this particular test is sufficient for the way in which
it is being used in practice. The best method for evaluating situations
in which concern exists about utilization of a test of any kind is to
document this in detail. This information can then be correlated with
clinical findings and pharmacy orders during the course of treatment.
With utilization and clinical data well documented,
the data from the manufacturer regarding the limitations of the test can
then be accurately assessed. The medical staff can then evaluate test
usage, both on an institutional and a per-provider basis. This can
generally be accomplished in the framework of laboratory quality
improvement, and is usually well received by the medical staff, if done
in the proper spirit. Doing so should discharge the responsibility of
both the lab and the institution to ensure that tests are both properly
offered and used.
If the analysis reveals that the methodology offered
is not appropriate for the use intended, the lab then has impetus to
institute a different one and probably an obligation to do so. If
the analysis determines that method and use are compatible, so much the
better. If the analysis determines that some physicians are
overutilizing the test, the medical staff can also address that issue.
Interestingly, liability stemming from BNP testing is
generally raised in quite a different context: failure to offer the test
at all. Because BNP has gained such a reputation for utility in the
diagnosis and management of congestive heart failure, some legal
commentators are raising the concern that it is an essential test for
primary care institutions and emergency rooms.
Barbara Harty-Golder is a pathologist-attorney consultant in Chattanooga, TN. She maintains a consulting law practice with a special interest in medical law. She writes and lectures extensively on healthcare law, risk management, and human resource management.
February 2004: Vol. 36, No. 2