Pharmacy OneSource Blog

Clinical Corner: Will Empiric Drug Therapy become a Thing of the Past?

Approximately 55% of patients receive an antibiotic during the course of their hospitalization; of those patients, about 40% are not receiving optimal therapy. It is estimated that a 30% reduction in broad spectrum antibiotic use would translate to a 26% decrease in C.diff.3

For decades it has taken many days to determine which organism was responsible for infection, and which antibiotics the organism was susceptible to. In the last few years, however, the time frame has dramatically changed with many rapid tests being introduced to the market. Molecular diagnostic tests are now capable of providing organism identification in hours instead of days.

In the not too distant future could empiric therapy become a thing of the past?

For example, approximately 22% of antibiotics prescribed in hospitals are for the treatment of lower respiratory tract infections. It is exciting to think about withholding antibiotics for a viral respiratory illness or discontinuing unnecessary antibiotics after only a single dose. With these new rapid tests, in less than an hour you can identify if you have a virus or a bacteria using a product like the BioFire film array from Biomerieux. This is a polymerase chain reaction test.2 The FilmArray’s Respiratory and Blood Culture Identifications panels are comprehensive and, combined, test for more than a hundred pathogens. FilmArray requires just 2 minutes of hands-on-time and returns results in about 1 hour.

A study that looked at outcomes in a children’s hospital 1 after the implementation of this product found that of the 771 tests performed, 597 (77.9%) were positive for viruses. The study is encouraging because it reported a decline in duration of therapy for antibiotics for these patients, but disappointing that there was not a decrease in the percent of patients that received antibiotics.


Another way to distinguish between bacterial and viral infections is to use procalcitonin. According to a study4, levels change rapidly in response to a bacterial infection. After induction, PCT increase is observed within 2-3 hours. Levels then rise rapidly, reaching a response after 6-12 hours.


Practice will need to change with this new technology and prescribers will need to be educated about the turnaround time for tests, the accuracy of these tests, and how to act on the results. Antibiotic overuse seems to be an issue with every facility that I speak to, so it is exciting that there are tools becoming available to tackle this important problem.

Is your lab already using newer technology like this or are they considering it? What experiences have you encountered as you worked to change prescriber practice?


1 Rogers B, Shankar P, Jerris RC, et al. Impact of a Rapid Respiratory Panel Test on Patient Outcomes.[epub ahead of publication].

2 Zaas AK, Burke T, Chen M, et al. A Host-Based RT-PCR Gene Expression Signature to Identify Acute Respiratory Viral Infection. Sci Transl Med 2013;5(203).

3 Vital Signs: Improving Antibiotic Use Among Hospitalized Patients. Website.

4Brunkhorst FM et al. Kinetics of procalcitonin in iatrogenic sepsis. Intensive Care Med. 1998 Aug:24(8)888-9.


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