Many people who believe they are allergic to penicillin are not, according to a new study published in the Annals of Emergency Medicine. Researchers in a Cincinnati ED used a skin test to check for penicillin allergy in 150 patients who said they were allergic to the drug. Only 13 tested positive, meaning more than 90% could take penicillin and related medications without suffering allergic reactions.

Some explanations are that people assume side effects are allergic reactions, or their doctors have erroneously assumed reactions are due to allergies, or they have outgrown a childhood allergy.

Penicillin alergy test kits are not widely available. The researchers used a test kit made in their own lab.