Penicillin Allergy Tests: How Accurate Are They?

Tests for penicillin allergy have low sensitivity and high specificity, according to the results of a recent meta-analysis.

“Without a proper diagnostic approach, many patients with a penicillin allergy label may unnecessarily receive second-line, broad-spectrum antibiotics, leading to an increased risk of drug failure, hospital-acquired infections, and higher length of stay,” the researchers wrote.

They sought to investigate the sensitivity and specificity of skin tests and specific IgE quantification for the diagnosis of penicillin/β-lactam allergy, examining data from 105 studies and 31,761 participants.

Overall, skin tests had summary sensitivity of 30.7% (95% confidence interval [CI] 18.9%-45.9%) and a specificity of 96.8% (95% CI 94.2%-98.3%), while specific IgE had summary sensitivity of 19.3% (95% CI 12.0%-29.4%) and a specificity of 97.4% (95% CI 95.2%-98.6%).

“Projected predictive values mainly reflect the low frequency of true penicillin allergy,” they wrote.

“Skin tests and specific IgE quantification appear to have low sensitivity and high specificity. Because current evidence is insufficient for assessing the role of these tests in stratifying patients for delabeling, we identified key requirements needed for future studies,” they concluded.

—Michael Potts


Sousa-Pinto B, Tarrio I, Blumenthal KG, et al. Accuracy of penicillin allergy diagnostic tests: A systematic review and meta-analysis. JACI. 2021;147(1):296-308.