It is vital that patients who suffer anaphylaxis have tests to accurately identify the cause, so they can avoid the drug in future. However these tests are currently very limited, because we don't have any diagnostic tools proven to confirm or refute a diagnosis of teicoplanin allergy. We have to make a 'best guess' diagnosis, leaving patients vulnerable to harm in the future, should they require antibiotics again. We need to reliably diagnose teicoplanin allergy to reduce this arm. Where a diagnosis of teicoplanin allergy is confirmed, patients and their doctors know to avoid it. Importantly, where allergy is excluded, teicoplanin can be safely used, avoiding alternatives that may be less effective, more toxic, and more expensive. This directly benefits individuals, saves the NHS money by reducing avoidable harm, and helps improve antibiotic stewardship at a population level - which in the long term helps reduce antibiotic resistance. The clinical need for this work has become imperative.