Allergy to penicillin. Comparison of "in vivo" and "in vitro" tests

Skin tests (SKT) and Lymphocyte Transformation Test (LTT) utilizing sodium penicillin G (PNG) and penicilloyl polylysine (PPL) and Rast to penicilloyl G were carried out on forty patients with a history of allergic reactions to penicillin, the results obtained indicated no statistically significant difference between the use of SKT or LTT in the diagnosis of allergy to penicillin (X2, p > 0,05), while the use of Rast showed a statistically significant difference (X2, p < 0,001) in favour of LTT and SKT. The use of either type of allergen (PNG or PPL) in LTT or SKT showed a significant difference in favour of the former (X2, p < 0,01).