Brief Reports

The impact of penicillin skin testing on clinical practice and antimicrobial stewardship



Penicillin skin testing (PST) is a simple and reliable way of diagnosing penicillin allergy. After being off the market for 4 years, penicilloyl‐polylysine was reintroduced in 2009 as PRE‐PEN. We describe the negative predictive value (NPV) of PST and the impact on antibiotic selection in a sample of hospitalized patients with a reported history of penicillin allergy.


We introduced a quality improvement process at our 861‐bed tertiary care hospital that used PST to guide antibiotic usage in patients with a history consistent with an immunoglobulin E (IgE)‐mediated reaction to penicillin. Subjects with a negative PST were then transitioned to a β‐lactam agent for the remainder of their therapy. NPV of skin testing was established at 24‐hour follow‐up. We are reporting the result of 146 patients tested between March 2012 and July 2012.


A total of 146 patients with a history of penicillin allergy and negative PST were treated with β‐lactam antibiotics. Of these, only 1 subject experienced an allergic reaction to the PST. The remaining 145 patients tolerated a full course of β‐lactam therapy without an allergic response, giving the PST a 100% NPV. We estimated that PST‐guided antibiotic alteration for these patients resulted in an estimated annual savings of $82,000.


Patients with a history of penicillin allergy who have a negative PST result are at a low risk of developing an immediate‐type hypersensitivity reaction to β‐lactam antibiotics. The increased use of PST may help improve antibiotic stewardship in the hospital setting. Journal of Hospital Medicine 2013;8:341–345. © 2013 Society of Hospital Medicine

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