Follow-up of patients with negative drug provocation tests to betalactams.

Drug allergy work-up in betalactam (BL) allergy is probably the most-developed drug-allergy evaluation at present [1]. During the last few years, the debate on whether one-day or several-day (prolonged) drug provocation test (DPT) should be performed in non-immediate reactions (i.e., occurring >1h after the last administered dose) in order to increase sensitivity has been ongoing and groups working in drug allergy diagnosis have been deploying pro and con arguments and studies in favour of either option [2-5]. The most acceptable way to validate a negative DPT is by studying its negative predictive value (NPV) in patients who are re-challenged to the negatively tested drug, in real-life therapeutic conditions [6,7]. This article is protected by copyright. All rights reserved.