Skin tests and specific immunoglobulin E (IgE) quantification had high specificity and low sensitivity in identifying patients who may develop a hypersensitivity reaction associated with penicillin exposure, according to study results published in the Journal of Allergy and Clinical Immunology.
Researchers conducted a systematic review and meta-analysis of 105 primary studies that reported a penicillin/β-lactam allergy in patients who received skin tests and/or specific IgE quantification. Only studies that compared these tests with a drug provocation test (DPT) were included. In the pooled analysis, there were 31,761 individuals. The accuracy of diagnostic tests was quantitatively assessed using bivariate random-effects meta-analyses in 27 studies.
In the meta-analysis of the 27 studies, skin tests featured a summary sensitivity of 30.7% (95% CI, 18.9%-45.9%) and specificity of 96.8% (95%CI, 94.2%-98.3%). The partial area under the summary receiver operating characteristics (ROC) curve for skin tests was 0.686 (I2 = 38.2%). Similarly, specific IgE featured a summary sensitivity of 19.3% (95% CI, 12.0%-29.4%) and a specificity of 97.4% (95% CI, 95.2%-98.6%). Specific IgE had a partial area under the summary ROC curve of 0.420 (I2 = 8.5%). Additionally, skin prick tests featured a summary sensitivity and specificity of 29.9% (95% CI, 15.0%-50.8%) and 95.1% (95% CI, 88.1%-98.0%), respectively.
This analysis was limited by the inclusion of only a small number of studies that performed DPT in patients with positive index and the possibility of selection bias.
The investigators wrote that “[a]s current evidence is insufficient for assessing the role of these tests in stratifying patients for delabeling, we identified key requirements needed for future studies.”
Some of the requirements included testing protocol standardization, details of index reactions (eg, clinical manifestations and timing), and presentation of results stratified by different reaction phenotypes and risk groups or publication of anonymous patient data.
Sousa-Pinto B, Tarrio I, Blumenthal KG, et al. Accuracy of penicillin allergy diagnostic tests: a systematic review and meta-analysis [published online May 21, 2020]. J Allergy Clin Immunol. doi:10.1016/j.jaci.2020.04.058