Table 4. Comparison of strategies to remove spurious β-lactam allergy labels (adapted from [3]).

Strategy	Methodology	Advantages	Disadvantages
Classic allergy diagnostics	H, ST, LT, PT	Highest safety, proven procedure, allergists, highest risk reduction for immediate reactions before PT, good NPV, cross-reactivities can be tested	High cost, resource- and time-intensive, too few testing options for affected patients, validity of laboratory testing insufficiently verified
Skin testing	ST	Minimizes risk for severe reaction, risk low for all immediate reactions, moderate risk reduction for exanthema	Skin test-negative exanthema and immediate reactions after testing not excluded with certainty, different significance of skin testing for different populations and β-lactam classes
Direct provocation	PT	Good NPV, well-tested in childhood in patients at low risk of non-severe reactions (e.g., uncomplicated exanthema in childhood infection), not resource-intensive	Risk for reactions higher, few data for use in adult exanthema, insufficient data for use in immediate reactions.
Standardized questioning (consideration of the medical history alone)	H	Majority of patients interviewed are not allergic, sometimes clear statements can be derived from H alone, resource-conserving	Residual higher risk has to be accepted, not very convincing for the patient, administration of the β-lactam only under direct medical supervision (as a measure for risk minimization)
Risk stratified approaches (application of algorithms)	Variable, depending on H	Different approaches depending on the H of the patient, therefore combines different strategies, good utilization of resources.	Complex courses of action that require clear rules, possibility of errors, validation so far only by limited observatory trials

H = history, ST = skin tests, LT = laboratory tests, PT = provocation tests, NPV = negative predictive value.