Eighty patients with past histories of penicillin allergy who required penicillin therapy were evaluated with several objective immunologic tests for the possibility of an allergic reaction to penicillin. All 68 patients with negative immediate skin tests to the major and minor penicillin skin test reagents tolerated penicillin without immediate or accelerated allergic reactions. Patients with positive skin tests had a high incidence of allergic reaction. Titer and antibody class (IgG or IgM) of hemagglutinating penicillin antibodies was not useful in predicting immediate allergic reactions but IgG titers were useful in predicting accelerated allergic reactions.
Voss HE, Redmond AP, Levine BB. Clinical Detection of the Potential Allergic Reactor to Penicillin by Immunologic Tests. JAMA. 1966;196(8):679–683. doi:10.1001/jama.1966.03100210049014